Hacksaw

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Hacksaw
x = 199, y = 102, rule = B3/S23 17b2o$18bo$91bo$91bobo$94b2o6b2o$52b2o24bo15b2o3bo4bo$53bo23b2o15b2o3b 2o4bo$34b2o17bobo5b2o13b2o13bobo11bo9bo$33bobo18b2o5b3o11b3o13bo13bo8b 2o$23b2o7b3o12bo15b2obo9b2o26bo$23bo7b3o13b4o12bo2bo10b2o23b2o$16b3o 13b3o4bobo6b4o11b2obo11bo$15bo3bo13bobo3b2o7bo2bo9b3o$14bo5bo13b2o4bo 7b4o9b2o$15bo3bo27b4o4b2o17b2o$16b3o28bo7bobo16bo$16b3o38bo$57b2o$40b 2o9b2o64b2o$39bo2bo7bo2bo63bo$39b3o9b3o61bobo$14b3o25b9o64b2o$13b2ob2o 23bo2b5o2bo$13b2ob2o23b2o2b3o2b2o134bo$13b5o169bo$12b2o3b2o163bo4bo$ 46bo136b5o$47bo$43bo3bo12bo$44b4o13bo$56bo4bo123b2o$57b5o120b3ob2o$ 177b3o3b4o$184b2o$15bo$15b2o$67b2o115bo$66bobo116bo$9bobo40bo12b3o8b2o 101bo5bo$7bo3bo40b4o8b3o10bo102b6o$2o5bo10b2o3b2o28b4o8b3o24bo$o5bo10b obo3bo2bo15bo10bo2bo9bobo18b3ob2o3bo$7bo11bo7bo7bo6b2o9b4o10b2o18b4o4b 2o$7bo3bo15bo6b2o16b4o35b2o$9bobo15bo24bo$23bo2bo38b2o16b2o$23b2o40bo 16bobo$81b3o$81b2o79bo$84b2o77bo$83b3o71bo5bo$158b6o2$84bo$83b2o2$57bo 126b2o$56b2o122b4ob2o$45b2o8b2o11bo26bo84b6o$45bo8b3o9bobo26b2o84b4o 12bo$55b2o8bobo12bo54b5o58bo$56b2o2b2o2bo2bo11b2o14bo38bo4bo54bo3bo$ 57bo2bo4bobo26bobo42bo55b4o$66bobo25bo2bo40bo20b4o27b3o$68bo26bo2bo59b o3bo25b2ob2o$162bo21b3o3b3o$95bo65bo33b4o$95b2o97bo3bo$172b2o24bo$171b 4o22bo$171b2ob2o$66b2o105b2o6b6o$65b3o27bo73bo10bo5bo$55b2o5bob2o12bo 15b2o71bobo16bo$55bo6bo2bo12b2o29b2o58bo15bo$62bob2o13b2o27bo64b2o$65b 3o11b3o11bo13bo9b2o52b2ob2o$66b2o11b2o10bobo13bo10bo17b2o33b4o$78b2o9b 2o16bo27bo2bo33b2o$78bo10b2o17bo29bo$89b2o18b2o27bo22b6o$91bobo41b2obo 21bo5bo$93bo42bo29bo$149b2obo2bo9bo$148b2o6bo$137bo12bobo3bo$136b2o15b 4o4$168bo$137bo29b2o$137b2o12bo14b2o8b2o$125bo23bobo13b3o9bo$125bobo 20bobo15b2o$114b2o12b2o9b2o6bo2bo16b2o$114bo13b2o9bo8bobo17bo$128b2o6b 2o6b2o3bobo$125bobo7b3o7bo5bo$125bo10b2o$139bo$139b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
Pattern type Sawtooth
Number of cells 687
Bounding box 199×102
Expansion factor 9
Discovered by Dean Hickerson
Year of discovery 1992

Hacksaw is an orthogonal sawtooth with expansion factor equal to 9 that was found by Dean Hickerson on August 7, 1992. The population in generation t = 385(9n) - 189 (n ≥ 1) is t/4 + 1079, but the population in generation 1155(9n - 179) (n ≥ 0) is only 977.

The pattern consists of two parts, a stationary shotgun and a set of puffers moving east. The shotgun produces, and usually destroys, a salvo consisting of a middleweight spaceship and two lightweight spaceships. The moving part consists of a blinker puffer 1 and two period 24 glider puffers whose output gliders destroy each other (with help from an accompanying middleweight spaceship). In generation 385(9n - 189) (n ≥ 1) (and 228 for n = 0), a salvo hits the back end of the row of blinkers, causing it to form a blinker fuse that decays at 2c/3. When the row is completely gone, a new row starts to form and a spark is produced. The spark is turned into a glider by an accompanying heavyweight spaceship; the glider is turned into a westward lightweight spaceship in generation 1155(9n - 127) (n ≥ 0) by interacting with the glider puffers. The 3-glider synthesis of the lightweight spaceship is due to David Buckingham. When the lightweight spaceship hits the shotgun in generation 2310(9n - 184) (n ≥ 0), another salvo is released, starting the cycle again.

The idea for this sawtooth pattern was suggested by Bill Gosper.

Image gallery

Videos

The hacksaw evolving though one of its cycles

See also

External links