Lifeline Volume 10

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Lifeline Volume 10
Lifeline Volume 10
Published in June 1973
Preceded by Volume 9
Succeeded by Volume 11
This page is a transcript of Volume 10 of the Lifeline newsletter
This article may contain spelling mistakes and/or errors that will not be corrected -- it is preserved in this way for history's sake
A QUARTERLY NEWSLETTER FOR ENTHUSIASTS OF JOHN CONWAY'S GAME OF LIFE

O     OOOOO OOOOO OOOOO O     OOOOO O   O OOOOO
O       O   O     O     O       O   OO  O O    
O       O   OOO   OOO   O       O   O O O OOO  
O       O   O     O     O       O   O  OO O    
OOOOO OOOOO O     OOOOO OOOOO OOOOO O   O OOOOO

NUMBER 10
JUNE 1973
• Editor and Publisher: Robert T. Wainwright

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Since publishing the last issue of LIFELINE, I received a unique letter which I am including in this issue in its entirety and without any editing. This reply is not only laid out in newsletter fashion but also includes a kaleidoscope of new and interesting discoveries. I certainly welcome any and all letters of this nature no matter how long or short!

As usual, I will present a cross-section of the new and more recent discoveries reported by all the readers who have taken the time and effort to reply.

Petrie's pentadecathlon, profound, and Prolific predecessors
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 640 ]] #C [[ HEIGHT 1024 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] o$b2o$2o3$b3o$3bo3bo$2bo3bo$6b3o4$6bobo$6b2o$7bo3$9b2o$9bobo$9bo!

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 960 ]] #C [[ HEIGHT 1024 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ X 1 ]] o$b2o$2o$20bo$10bo7b2o$9bo9b2o$9b3o4$14bo$9b2o2b2o$10b2obobo$9bo4$4b3o $6bo$5bo6b2o$11b2o$13bo2$17bo$16b2o$16bobo!

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 640 ]] #C [[ HEIGHT 1024 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ X 1 ]] 2bo$obo$b2o$9bo$8bo$3o5b3o$2bo$bo$6b2o$5b2o$7bo!

The glider arrangements shown on this cover page of LIFELINE Number Ten are described in the previously mentioned letter sent in by Douglas G. Petrie of Lake Oswego, Ore. These patterns discovered by Petrie produce respectively in a varying number of generations, the pentedecathlon(!), Conway's heavyweight spaceship(!!), and Corderman's Switch Engine(!!!). Details of these reactions and other newsworthy events are described in Petrie's letter which begins on page three. Is there pattern beside Gardens of Eden that can not be constructed with gliders?

Lifequote submitted by Mark Linimon of Houston, Tx:
'Life is too important a matter to be taken seriously.'
. . . Oscar Wilde

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Class E, Evolutionaries, Exercises, Events, Et. cetera . . .
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 64 ]] #C [[ WIDTH 704 ]] #C [[ HEIGHT 704 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] bo$2bo$3o2$5b2o$b2o2b2o$b2o!

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 64 ]] #C [[ WIDTH 640 ]] #C [[ HEIGHT 512 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] 2o2b2o$b2ob2o$o$6bo$6b2o$5bobo!

In keeping up with the new and exciting series of glider(s) and block(s) collisions reported last issue, Dave Filpus of East Lansing, Mi. submits the following reaction of a single glider and two blocks which in 113 generations yields a glider (reflected 180 degrees) and three blocks!

Additionally, Peter Raynham of Sarnia, Ontario, Canada submits the following collision of a block and two gliders which in 47 generations results in two gliders (reflected 90 degrees) and three beehives!

The fates of the two unknown nonominoes introduced last issue were first discovered and sent in by Robert Bison of Hopewell Jct., N.Y. and then later by Bryan Drake of Lansing, Mi. and Harvey Lerman of Maitland, Fla. Incidentally, Drake supplied some very nice Polaroid photographs of these final populations that were left on the screen of the IMLAC device described last issue. A summary of these results as submitted by Bison follows:

Nonomino Age Maximum Population Final Pop Final Area Census
N-1 1451 536(@439) 291 =160x180 29 blocks, 2 tubs, 5 beehives, 3 ships, 2 loaves, 1 long boat, 1 fleet, 13 blinkers, 6 gliders.
N-2 2925 562(@2110) 388 =140x160 31 blocks, 1 tub, 4 boats, 17 beehives, 4 loaves, 3 ponds, 12 blinkers, and 10 gliders!

Additionally, Bison notes that the Filpus-Karplus glider-blocks collision described last issue (p.2) goes to 3360 generations after spawning 15 gliders (!) for a Final population of 457 (max was 769 @2931). During its history it expanded to 160x200 (@2592) before settling down to within 150x180.

A spaceship collision resulting in an unusual still life has been reported by D. R. Mc Entee of St. Louis, Mo. Shown below are two lightweight spaceships colliding to form a 14-bit stable object.
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 1248 ]] #C [[ HEIGHT 640 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ X 1.5 Y 5 ]] #C [[ LABEL 6.5 12 8 "even number\nof cells\napart" ]] #C [[ COLOR POLY Black ]] #C [[ POLYALPHA 1 ]] #C [[ POLYLINE 4.5 9.5 8.5 9.5 8 ]] #C [[ POLYLINE 4.5 9.5 4.5 9 8 ]] #C [[ POLYLINE 8.5 9.5 8.5 9 8 ]] #C [[ ARROW 17.5 4.5 21.5 4.5 6 ]] #C [[ LABEL 28.5 12 8 "14-cell\nstable\nconfiguration" ]] 3bo$4bo23b2o$o3bo21bo2bo$b4o21b3o$9b4o16b3o$9bo3bo14bo2bo$9bo18b2o$10b o!
Additionally, Raynham submits the following four-glider collision which also forms a 14-bit still life.
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 672 ]] #C [[ HEIGHT 640 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] 5bo$6bo6bo$4b3o5bo$3o9b3o$2bo13b3o$bo14bo$17bo6$7bo$7b3obo$10b2o$7b2o$ 7bob3o$11bo!

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Reader Reply . . .
May 2, 1973

Robert Wainwright
LIFELINE Editor

Dear Sir,

I was glad to receive copies of all the newer LIFELINEs in the mail recently. Some general comments: I notice that the newsletter is now being held to a limit of eight pages, and when rereading the "Coming Events" notices I get the impression thar a number of interesting items are, because of this limitation, being withheld. If the reason for the limit is cost rather than some other factor (taking too much of your time?), I for one would be willing to kick in more money for a subscription. As far as the articles printed went, most were quite interesting (but, please, don't go overboard on the occult symbology). I strongly hope that the next issue will include something about glider logic circuitry. Everett Boyer ought to be keeping you informed of the rather extensive work he and I have done in that field, but I would also Like to see what others might have done -- I can't believe we are the only ones working on computer design.

Following are some recent discoveries of mine, of varying importance:

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 608 ]] #C [[ HEIGHT 320 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] bo11b2o$obo4bo6bo$7bo4bo$2bo2bo3bo2bo$2b2o6bo$3bo!

a time bomb

The ordinary-looking object at right has a very un-ordinary history: its final population is infinite! This (along with a few relatives of similar structure) is the smallest single object known to achieve infinite growth. You may recognize it as a cousin of the switch engine puffer shown in #4 p.1.

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 832 ]] #C [[ HEIGHT 768 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ COLOR 0 White ]] #C [[ COLOR 1 Black ]] #C [[ COLOR 2 Darkgray ]] #C [[ COLOR GRID 229 229 229 ]] #C [[ LABEL 15 18 8 "gen. 14" ]] #C [[ LABELT 0 0 0 ]] #C [[ LABEL 11 5 8 "gen. 0" ]] x = 22, y = 20, rule = immigration 6.3A6.2B$.3B2.A7.B.B$B2.B3.A8.B3.A$3.B15.2A$3.B15.A.A$B.B5$5.2A8.2B$ 4.A2.A8.B$4.A.A9.B.A$2.2B.A3.A7.2A$.B2.B3.A.A$.B.B3.A2.A$2.B3.B.2A$5. B.B$4.B2.B$5.2B!

hybrid objects

Following a suggestion by Parrello and Tetenbaum (#7 p.7) I have used "Immigration" rules on about 20 previously known collisions in order to determine the exact parentage of the resultant patterns; in only two cases did the final census include both types of live bits. These are illustrated at the right. In view of their rarity, any further examples of mixed populations that people might discover would be of interest, and in particular, any reaction that results in an allied glider, (such as glider-toad, #9 p.5) would be noteworthy. There are two 2-g1ider collisions whose result is a single glider each; in both cases the new glider is shown to be produced by a 180° reflection of one of the original gliders.

Addendum: Boyer has just informed me that three glider-blinker collisions result in a hybrid ship, a hybrid loaf, and a hybrid pond, respectively. EN: any others?

Enclosed with this letter is a list of 121 12-bit Class I objects which was compiled jointly by Boyer and myself. There may still be some missing, but not many. It is noteworthy that out of the entire list only one object (the half-fleet) has yet been reported to result from a "naturally-occurring" reaction.

EN: see 23,5 on next page.

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#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 2232 ]] #C [[ HEIGHT 3192 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ GRIDMAJOR 5 ]] #C [[ X -0.5 Y 2.5 ]] #C [[ LABEL -2 124.5 8 "1" ]] #C [[ LABEL -2 119.5 8 "2" ]] #C [[ LABEL -2 114.5 8 "3" ]] #C [[ LABEL -2 109.5 8 "4" ]] #C [[ LABEL -2 104.5 8 "5" ]] #C [[ LABEL -2 99.5 8 "6" ]] #C [[ LABEL -2 94.5 8 "7" ]] #C [[ LABEL -2 89.5 8 "8" ]] #C [[ LABEL -2 84.5 8 "9" ]] #C [[ LABEL -2 79.5 8 "10" ]] #C [[ LABEL -2 74.5 8 "11" ]] #C [[ LABEL -2 69.5 8 "12" ]] #C [[ LABEL -2 64.5 8 "13" ]] #C [[ LABEL -2 59.5 8 "14" ]] #C [[ LABEL -2 54.5 8 "15" ]] #C [[ LABEL -2 49.5 8 "16" ]] #C [[ LABEL -2 44.5 8 "17" ]] #C [[ LABEL -2 39.5 8 "18" ]] #C [[ LABEL -2 34.5 8 "19" ]] #C [[ LABEL -2 29.5 8 "20" ]] #C [[ LABEL -2 24.5 8 "21" ]] #C [[ LABEL -2 19.5 8 "22" ]] #C [[ LABEL -2 14.5 8 "23" ]] #C [[ LABEL -2 9.5 8 "24" ]] #C [[ LABEL -2 4.5 8 "25" ]] #C #C [[ LABEL 4.5 131 8 "1" ]] #C [[ LABEL 9.5 131 8 "2" ]] #C [[ LABEL 14.5 131 8 "3" ]] #C [[ LABEL 19.5 131 8 "4" ]] #C [[ LABEL 24.5 131 8 "5" ]] #C [[ LABEL 29.5 131 8 "6" ]] #C [[ LABEL 34.5 131 8 "7" ]] #C [[ LABEL 39.5 131 8 "8" ]] #C [[ LABEL 44.5 131 8 "9" ]] #C [[ LABEL 49.5 131 8 "10" ]] #C [[ LABEL 54.5 131 8 "11" ]] #C [[ LABEL 59.5 131 8 "12" ]] #C [[ LABEL 64.5 131 8 "13" ]] #C [[ LABEL 69.5 131 8 "14" ]] #C [[ LABEL 74.5 131 8 "15" ]] #C [[ LABEL 79.5 131 8 "16" ]] #C [[ LABEL 84.5 131 8 "17" ]] 2$53b2o8b2o9bo7bo$4b2o8b2o9b2o7bo9bo8bobo7bobo7bobobo4b3o$3bo2bo6bo2bo 7bo2bo5bobo7bobo9bo9bo6bobob2o7bobo$3bobobo5bobo8bobo6bobo7bobo9b3o7b 3o4bobo9bob2o$2b2obobo4b2obobo4bobob2o4b2obobo4b2obob2o9bo9bo4b2o9bo$ 6bo9b2o4b2o12bobo7bobo8bo9bobo13b2o$37bo19b2o9bo3$7bo$6bobo7b2o8b2o8b 2o8b2o8bo9bo9bo9bo$5bobo7bobo7bobo7bobo7bobo7bobo7bobo7bobo7bobo$4bobo 7bobo8b2o8b2o8b2o8b2o8b2o8b2o8b2o$3bobo7bobo7b2o8b2o6bob2o8b2o8b2o8b2o 8b2o$2bobo7bobo7bobo6bo2bo6b2obo7bobo9bo7bobo5bobobo$3bo8b2o8b2o7b2o 18bobo10bobo5bo7b2o$52bo12b2o4b2o3$6b2o18b2o17b2o$7bo9b2o8bo9b2o7bo15b 2o10b2o7b2o$5bo9bo2bo6bo9bo2bo6bo9bob2o3bobo8bobo6bo2bo$5b2o8b2o8b2o8b 2o8b2o8b2obo4b2o8b2o8b2o$3b2o8b2o6bob2o6bob2o6bob2o6bob2o$bo2bo6bo2bo 6b2obo6b2obo6b2obo6b2obo8b4o6b4o6b4o$b2o8b2o50bo2bo6bo2bo6bo2bo4$12b2o 10b2o17b2o8b2o$b2o9bo12bo9b2o6bo10bo$bo2bo9bo8bo9bo2bo7bo8bo9bo2bo7bo 2bo5b2o$3b2o8b2o8b2o8b2o8b2o8b2o8b4o7b4o5b2o2$3b4o6b4o6b4o6b4o6b4o6b4o 6b4o5b4o7b4o$3bo2bo6bo2bo6bo2bo6bo2bo6bo2bo6bo2bo6bo2bo5bo2bo7bo2bo$ 84b2o2$37b2o$28b2o8bo18b2o$27bobo7bo9b2o9bo16b2o10b2o$3b2o10b2o9bo9bo 9bobo8bo8b2o7bobo8bobo$3b2o10b2o8bo9bo9bo10bo4b2o2bo2bo8bo2b2o3bo$24bo 9bo5b2o2bo6b2o2bo5bo2bo2b2o3b2o2bo4bo2bo$3b4o6b4o6bo9bo6bo2bo7bo2bo7b 2o8bo2bo5bobo$2bo3bo5bo3bo3bobo7bobo8b2o9b2o19b2o7bo$2b2o8b2o6b2o8b2o 3$7b2o$8bo22b2o8b2o3b2o3b2o8b2o$7bo3b2o3b2o3b2o3bo4bobo3b2o2bobo3bo3bo bo7bobo10bo9bo$b2o3bo5bo2bo2bo3bo2bobo5bo2bobo4bo2bo6bo9bo7bobobo5bobo bo$2bo2bo6bobo2b2o3bobo2bo5bobo7bobo7bobo7bob2o4b2o2bo5b2o2bo$2bobo8bo 9bo3b2o5bo9bo9bobo7bo2bo7bob2o6bobo$3bo52bo9b2o8bobo7bobo$56b2o29bo4$ 22bo38b2o$4b2o5bob2o6bobo12b2o7b2o4b2o2b2o5bo2b2o8b2o8b2o$bobo2bo4b2o 2bo6bo2b2o8bo2bo5bo2bo3bo2bo2bo4bobo2bo6bo2bo6bo2bo$b2o2bo8bo2b2o4b2o 2bo6bo2bobo3bo2bobo3b2o2bobo4bo2bobo2bobo2bobo4bo2bobo$6b3o6b2obo7bobo 2bobo4bo3bo4bo9bo9bo3b2o4b2o3bo4b2o$8bo18bo3b2o8bo40b2o$41b2o3$62b2o8b o8bo$11b2o50bo8b3o6b3o$b2o9bo11b2o5bob2o10bo9bo7bobo9bo8bo$bo2b2o6bob 2o5bobo2bo4b2o2bo8bobo7bobo7bobo7bobo6bobo$2b2o2bo6bo2bo4b2o2bobo6bobo 6bobobo7bobo7bobo7bobo6bobo$5bobo7bobo8bobo6bobo5bo3bo4b3o2bo9bo9bo7bo bo$6b2o8b2o9bo8b2o4b2o3b2o3bo4b2o8b2o8b2o7bo4$3bo8bo9bo14bo9bo8b2o8b2o $3b3o6b3o7b3o11bobo7bobo7bo9bo9b2o8b2o$6bo8bo9bo11bo9bo9bo9bo9bo9bo$5b obo6bobo7bobo7b3o7b3o7b3o7b3o7b3o7b3o$4bobo6bo2bo7bo2bo5bo9bo9bo9bo9bo 9bo$3bobo7bobo9bobo4bobo7bobo7bobo7bobo7bobo7bobo$4bo9bo11bo5b2o9b2o7b 2o9b2o6bobo9bobo$72bo11bo4$6b2o39b2o8b2o$7bo9b2o9b2o7b2o9bo9bo22bob2ob o$4b3o6b2obobo8bobo6bobo8bo9bo3bob2ob2o5b2ob2o3b2ob2obo$3bo6bobob2o5bo b2obo5b2obo5bob2obo6b2obo4b2ob2o2bo2bo2b2o2bo8bo$2bobo5b2o9b2ob2o4bo2b 2o6b2ob2o5bo2b2o11b2o2b2o4b2o8b2o$2bobo25b2o19b2o$3bo3$36bo$17b2o7b2o 6b3o4b2o9b2o8b2o8bo9bo$3b2obo10bo8bo6bo7bo11bo9bo7bobo7bobo$bo2b2obo6b 2obo5b2obo6b2o7b3o7bo9bo4b2o3bo9bo4b2o$b2o4bo3bobob2o5bob2o8bo9b3o6b3o b2o4b3o2bo4b3ob2o4b3o2bo$7b2o2b2o9bo11bobo10bo7b2obo6b2o8b2obo6b2o$21b 2o12b2o9b2o5$26b2o47b2o8bo$b2o10bo9bo2bo6bo3b2o4bo2b2o5b2o9b2o8bo2bo6b obo$bo5b2o3bobo7bobobo5bobobobo3bobo2bo4bobo8bobo7bobobo5bobobo$2b3obo bo2bo2b3o4bo2b2o5bo2b2o5bo2bobo4bo2bobo5bo2bob2o3bo2b2o5bo2bobo$4b2o5b 2o4bo3b2o8b2o8b2o2bo5b2o2bobo4b2o2bobo3b2o8b2o2bo$16b2o38bo5$5bo8b2o6b 2o9b2o8b2o7b2o9b2o8b2o$4bobo6bo2bo5bo2bo6bo2bo6bo2bo7bo10bo9bo9b2o$3bo bo7b2obo6b2obo6b2obo6b2obo5bo9bo9bo9bo2bo$2bo2bobo7bo9bo9bo9bobo4b2o8b 2o8b2o2b2o4b2o$2b2o2b2o7bobo7bobo7bobo7bobo6bob2o6bob2o6bo2bo6b4o$16b 2o8b2o8b2o8bo7b2obo6b2obo6b2o8bo2bo!

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Reader Reply . . .
page 2
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 672 ]] #C [[ HEIGHT 448 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ X 0.5 Y 2 ]] #C [[ LABEL 3.5 10 8 "gen. 0" ]] #C [[ LABEL 14 10 8 "gen. 3" ]] 2bo$obo9b2o$b2o9bobo$4bo10bo$3bo12bo$5b3o7b2o$5bo$6bo!

ERRATA: The "race against time" scenario (#3 p.14) will not work as shown; the correct form is pictured here. Also, in the table of 3x3 patterns (#9 p.4) note that A10=D11, E11=H10, so the number of unique arrangements is actually 102.

EN: thanks, I missed that.

By using eaters instead of blocks for shuttle-stabilizers (#3 p.5) it is possible to stack glider guns as close as 20 spaces apart, rather than 24 as reported in #9 p.5.

EN: I would still be satisfied to see a period 48 NEWBREEDER!

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 864 ]] #C [[ HEIGHT 288 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ X 0.5 Y 0.5 ]] #C [[ LABEL 3.5 4.5 8 "(A)" ]] #C [[ LABEL 15 4.5 8 "(B)" ]] 3bo13bo4bo$b2ob2o12bo$6bo12b3o$o20bo!

Now that Boyer's procrastination quotient has appeared, readers might be interested in trying to find the most procrastinating ancestor of each of the common terminal forms. For the blinker and the beehive the objects reported by Thompson (#8 p.5) will surely hold the record. Presented here as further candidates are (A) an interchange ancestor (21 gens., PQP=.167), and (B) a traffic lights ancestor (28 gens., PQP=.333).

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 960 ]] #C [[ HEIGHT 1080 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ ARROW 18 9.5 21 9.5 5 ]] #C [[ ARROW 18 34.5 21 34.5 5 ]] #C [[ LABEL 19.5 12.5 6 "12" ]] #C [[ LABEL 19.5 37.5 6 "28" ]] $11bo$11bobo$11b2o$7bo$8b2o$7b2o2$29bo$28bo2bo$28bo2bo$30bo2$6b2o$7b2o $6bo$10b2o$10bobo$10bo7$11bo$9b2o$10b2o$25b3o3b3o$7bo$8b2o13bo4bobo4bo $7b2o14bo4bobo4bo$23bo4bobo4bo$25b3o3b3o2$25b3o3b3o$23bo4bobo4bo$10b2o 11bo4bobo4bo$9b2o12bo4bobo4bo$11bo$25b3o3b3o$7b2o$8b2o$7bo!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 768 ]] #C [[ HEIGHT 1272 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ X 1 Y 0.5 ]] #C [[ ARROW 5 9 5 12 5 ]] #C [[ ARROW 20 19 20 22 5 ]] #C [[ ARROW 20 38 20 41 5 ]] #C [[ LABEL 2 10.5 6 "11" ]] #C [[ LABEL 17.5 20.5 6 "6" ]] #C [[ LABEL 17.5 39.5 6 "4" ]] 7bo$7bobo6bo$7b2o8b2o$16b2o$obo23bo$b2o4b3o9b2o3b2o$bo5bo11bobo3b2o$8b o11b2o2$17b2o$18bo$18bobo$19b2o2$23bo$6b2o14b2o$5bobo14bobo$5b2o8$22b 2o$20bo4bo$20bo3bo$21b4o$17b2o$18bo$19bo$19bo2$22bo10$23bo$21bo3bo$26b o$20bo5bo$21b6o!

As a number of readers probably know, in the multitude of glider collisions can be found methods for constructing almost all of the familiar Class I&II objects. Two unusual examples are illustrated at the left. In Class III, ways of making light or medium spaceships have long been known, but as yet no one has reported any method to build the heavy spaceship. This hole has now been filled. Shown at the right is a complex reaction between three gliders, a ship, and an eater which produces a heavy spaceship in ten generations. Shown also is one of many three-glider collisions which results in a ship. Since two gliders react to form an eater, making a heavy spaceship therefore requires a total of eight gliders. Using this mechanism a P60 heavy spaceship factory can probably be built, but in the present state of the art such a factory would require about 25 P30 glider guns. Perhaps future collision discoveries will allow simplification.

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 48 ]] #C [[ WIDTH 960 ]] #C [[ HEIGHT 384 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ ARROWT 0 0 0 ]] #C [[ ARROW 6.5 1.5 8.5 1.5 7 ]] #C [[ COLOR POLY White ]] #C [[ POLYALPHA 0.5 ]] #C [[ POLYT 0 0 0 ]] #C [[ POLYFILL -0.5 2.5 0.5 2.5 0.5 3.5 -0.5 3.5 -0.5 2.5 64 ]] 2b2o7bo2bo$b4o10bo$b2ob2o4bo4bo$o2b2o6b5o!

In #7 p.4 there were presented several examples of objects which, when attacked by a virus, would reproduce themselves. Another "friendly" virus has now come to light, one which stimulates growth rather than reproduction. A spaceship of any length (including overweight ones) with a virus attached as shown will immediately turn into a spaceship of the next larger size. This reaction is more important than might first appear; it is vital to the heavy-spaceship construction described earlier.

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 896 ]] #C [[ HEIGHT 480 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C Note that the switch engine an block syntheses are placed #C incorrectly. They should be one cell further apart. The placement #C of the switch engine and block in the pattern labeled "gen. 6" is #C correct. bo3bo12bobo$2bo2bobo10b2o$3o2b2o12bo$22bo$21b2o$9bo11bobo$8b2o$8bobo$ 4b2o$3bobo$5bo!
gen. 0

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 896 ]] #C [[ HEIGHT 480 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ X 1 Y 1.5 ]] 13b2o$3o10b2o$bo$bo2bo$bo2bo$2bobo!
gen. 6

With various rather complicated collision scenarios a number of Class IV patterns can be produced, too. A new and surprisingly simple construction of this nature was recently discovered: six gliders colliding to form a puffer train. Gen. 6 at right is the same as gen. 2 of the pattern pictured in #4 p.1.

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page 3
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 720 ]] #C [[ HEIGHT 600 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ GRIDMAJOR 5 ]] #C [[ X 3 Y 1.5 ]] #C [[ POLYALPHA 0.3 ]] #C [[ POLYFILL 9.5 13.5 10.5 13.5 10.5 14.5 9.5 14.5 9.5 13.5 64 ]] #C [[ POLYFILL 11.5 18.5 12.5 18.5 12.5 19.5 11.5 19.5 11.5 18.5 64 ]] #C Note that the bottom two gliders should be moved northeast by one #C cell as noted by the gray cells. 2$2bo$3b2o$2b2o3$3b3o$5bo3bo$4bo3bo13bo$8b3o11bo$21bobo$22bo$22bo$22bo $7bobo12bo$7b2o12bobo$8bo13bo$22bo2$10b2o$10bobo$10bo!

gen. 0 gen. 9

By now ways are known to form from glider collisions almost all of the "significant" objects or patterns, including eaters, pentadecathlons, both major types of shuttle, the three basic orthogonal spaceships, both glider guns, and two of the three types of puffer train. (For completeness, the simplest pentadecathlon-forming collision I know of is shown here.) "Significant" in this case refers to all objects which might prove essential to such large-scale constructions as puffer train factories, a p31 glider gun, glider logic circuitry, or a pattern capable of self-replication. Still missing from the list is any method of producing "Schick's Flying Machine". Why bother with these collisions at all? For one thing, any pattern able to reproduce itself must entirely be composed of objects which can be created with glider collisions; we now have a wide variety of objects which might be used to build such a pattern. For another, it keeps me off the streets and out of trouble. (Regarding the question (#9 p.2) concerning the purpose of LIFE, the most practical result I have seen is the prevention of boredom among computer programmers.)

That's all for now; more to follow later on, including more results obtained in collaboration with Boyer.

Sincerely yours,
Douglas G. Petrie
Enclosure: 12-bit objects. Lifequote:
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 32 ]] #C [[ WIDTH 640 ]] #C [[ HEIGHT 640 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ GRIDMAJOR 10 ]] #C [[ X 1 ]] 2$5bo8bo$5b3o5bobo$3b2o3bo3bobobo$4bo2bo4bobobo$4bobo6bobo$5bo8bo4$5b 2o$5bo7bo$6bo6b3o$3b4o9bo$3bo9b2obo$4bo8b2ob2o$3b2o!
EN: these four and p.4.

 'Life is very short
       and there's no ti i
                           i
                            i
                             i
                               i me . . . '
. . . Paul and John
Reader Brief . . .

Philip Cohen of Aliquippa, Pa.: 'I may have mentioned this before, but - of the 10,000's of possible 8-bit figures consisting of an R-pentomino and a Lifeline vol10 fig 06 03.png tromino at a greater or lesser distance, isn't it likely that at least one grows to infinity? It would seem worthwhile to investigate a dozen or so randomly chosen block sites to see if there is a significant change in any of the Life histories; if not, the speculation becomes rather less likely. Has it been tried?

EN: does anyone have a handle on the number of these combinations? (also for R-pentomino and a single blinker); try:
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 64 ]] #C [[ WIDTH 576 ]] #C [[ HEIGHT 448 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] b2o$2o$bo$o$2o!

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Lifeobservation . . .
SOME EQUIVALENT GLIDER PREDECESSERS

Anyone who plays life regularly knows that the alteration in position of even a single bit in a pattern can alter considerably the final census. Patterns which can be so altered and still produce identical output we call equivalent. For example, A is the glider predescessor heptomino discovered by Thompson. B and C show how the end bit can be moved around without destroying the pattern's identity- for all three produce the same glider in the game generation(4) occupying the same position in the matrix.

D and E are another case in point. Both of these patterns - differing from each other by the dislocation of a single bit - produce a single glider fleeing a set of traffic lights.

F is perhaps the most remarkable example I have to offer. Structurally it is a glider connected to a latent block. In Practice the latent block may as while not even exist, for the glider is alone in the field in the sixth generation, occupying the same position as it would have had it started out alone.

#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 1800 ]] #C [[ HEIGHT 240 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 3 ]] #C [[ Y -1 ]] #C [[ LABEL 2 -3 8 "A" ]] #C [[ LABEL 12 -3 8 "B" ]] #C [[ LABEL 22 -3 8 "C" ]] #C [[ LABEL 38 -3 8 "D" ]] #C [[ LABEL 52 -3 8 "E" ]] #C [[ LABEL 68 -3 8 "F" ]] 5o5b5o5b5o9bo2bob3o6bob2ob3o10b2ob2o$obo9bo9bo13bobo13bo13bobobo$10bo 8bo14bo13bo17bo!

Harry J. Riley of Trenton, N.J.

Additionally, Curt Gibson of New York, N.Y. notes that: Lifeline vol10 fig 07 02.png and Lifeline vol10 fig 07 03.png have identical results (traffic lites) in exactly the same position and in exactly the same number of gens.

Lifemerick:
An eager young Lifeman named Draper
Played all night by the light of a taper,
But, excessively tired,
He quite soon expired,
So they buried him, wrapped in squared paper!
. . . J.E. Still of Wembley, Middlesex, England

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LIFEXPLAINATIONS . . .

Tom Du Bois of Hawthorne, N.Y. has noted a surprising phenomenon in Life regarding hollow block objects. In all cases investigated up to order sixteen, the resultant census contains still lifes composed of bits with either 2 or 3 neighbors but never both.

Eric A. Haines of Moorestown, N.J. has noted the same phenomenon regarding solid block objects. In all cases investigated up to order nine, the census never contained a common 2/3 type still life.

Henrik Bjurstrom of Uppsala, Sweden in studying all solid rectangular objects up to ten by ten, has neverseen a census containing a common 2/3 type still life.

These Lifexplainations are very unusual since still lifes are almost always composed of bits with both 2 and 3 neighbors. In fact, of all the 60,000 still lifes of 20 or less bits (conservative estimate), there are only nine known to the writer. See table below showing this distribution:

Still Life Structure Data
-SIZE- 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
2 + 3 0 1 3 3 7 10 25 46 121 210 474 ? ? ? ? ? ?
2 only 1 0 2 1 2 0 0 0 0 0 0 0 0 0 0 0 2
3 only 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Totals 2 1 5 4 9 10 25 46 121 210 474 ? ? ? ? ? ?

The smaller ones should be obvious to the seasoned Lifenthusiast. Can you identify all nine? I'll print results of anyone with more in No. 11. EN: how long can these generalities possibly last?


Reader Brief . . .
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH ]] #C [[ COLOR LABEL Gray LABELZOOMRANGE -2048 2048 LABELSHADOW OFF ]] #C [[ COLOR ARROW Black ARROWZOOMRANGE -2048 2048 ARROWSHADOW OFF ]] #C [[ COLOR POLY Black POLYZOOMRANGE -2048 2048 POLYSHADOW OFF POLYALPHA 0.15 ]] #C [[ THUMBZOOM 24 ]] #C [[ WIDTH 2016 ]] #C [[ HEIGHT 552 ]] #C [[ SUPPRESS ]] #C [[ THUMBSIZE 4 ]] #C [[ ZOOM 5 ]] #C [[ X 30 ]] #C [[ LABEL 48 1 6 "P48" ]] #C [[ LABEL 74 1 6 "P48" ]] #C [[ LABEL 48 19 6 "P48" ]] #C [[ LABEL 74 19 6 "P48" ]] #C [[ LABEL 40.5 10 6 "B" ]] #C [[ LABEL 81.5 10 6 "B" ]] #C [[ ARROW 35 10 38 10 5 ]] 2o19b2o$obo17bobo$3bo15bo$4bo13bo$5bo11bo$6bo9bo$7bo7bo$8bo5bo$9bo3bo$ 10bobo$11bo$10bobo$9bo3bo$8bo5bo$7bo7bo$6bo9bo$5bo11bo$4bo13bo$3bo15bo $obo17bobo$2o19b2o!

R.J. Best of Miami, Fla. reports that an order twenty-one 'hooked cross' yields in 87 generations, a group of four pulsars with two extra beehives. Best ran this in four seconds on homemade device that outputs the results on a T-V like device.

COMING EVENTS:

  • Neal'sgame - an exciting and new biocolony simulation
  • The 'Blinker-Tee' family
  • Life on a small doughnut - is it alive?
  • more local Lifeclub news
  • a four-glider pentadecathlon predecessor
  • other exotic n-glider collisions
  • a period 92 Slogun!
  • a period 76 pseudo spaceship
  • a period 14 pseudo oscillator

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