Lifeline Volume 5
|Lifeline Volume 5|
|Published in||September 1972|
|Preceded by||Volume 4|
|Succeeded by||Volume 6|
|This page is a transcript of Volume 5 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 5 SEPTEMBER 1972• Editor and Publisher: Robert T. Wainwright •
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Activity regarding Life and LIFELINE is beginning to pick up again after a rather quiet spring. In May I sent out a status report with a questionnaire to all 700 of the previous correspondents. The response has been very encouraging and after thinking about the fate of LIFELINE for awhile, I have decided there is definitely enough interest to keep it going with some help from other readers like yourself. I have contacted and made arrangements for a local commercial service to handle the very time consuming burden of mailing label preparation and printing. For this reason, I have decided to oversee the entire effort myself assuming most of the creating articles and material will be supplies by various 'satellite' groups.
The last sheet of this newsletter titled LIFESAVER is a renewal in questionnaire form which can be conveniently detached, folded, and mailed. The name and address information to be included in the return will be used to update the computer file of all 700 existing correspondents. If a reply is not received, I will assume you are no longer interested in obtaining LIFELINE. With regard to the new subscription procedure, my feeling right now is that if someone submits a usable article, he would be entitled to a years subscription at no cost. On the other hand, you may elect to be a regular subscriber and simply pay the nominal annual rate which is explained in the LIFESAVER. Remember, only your completed and returned LIFESAVER will guarantee a subscription to LIFELINE.
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For the benefit of those of your who have not yet had the pleasure to read Martin Gardner's popular October 1970 column in Scientific American, I will now summarize Conway's original Life rules and also suggest a convenient method to play the game.
Life is based on cellular automata theory and uses the two-dimensional square space which is simply a matrix or grid. Each square or cell within this grid has two possible states: either empty or full (that is occupied with a 'bit'). Each cell also has a set of eight surrounding neighbor cells that can influence its own state.
A cell's state will change according to a set of transition rules that aply simultaneously to every cell in the space. These rules are based on both the current state of the cell and also the collective state of its neighbors and need only consider and be defined for a cell going from empty to full (birth) or from full to empty (death). These possible combinations of state change are shown here to the right.
Conway's specific rules are the key to Life and will now be described:
Births: each empty cell with exactly 3 neighbors whose cells are full (contain a bit) is a birth cell. A bit is placed in it for the next move.
Deaths: each full cell (containing a bit) requires 2 OR 3 neighbors to survive for the next move. Every bit with four or more neighbors dies from overpopulation and every bit with one or no neighbors dies from isolation.
When Conway originally stated his rules, he presented a third rule for survivals but here we have included it with the death rule since it is implied by same. It is very important to understand that all births and deaths occur simultaneously. Together they constitute a single move, or as we shall call it, a generation, in the complete Life history of an initial pattern which may be constructed of cells occupied with any arrangement of bits. Any given pattern will then change its state in discrete steps by recursively applying Conway's rules.
A simple procedure of steps is suggested on the top of page three for manually making these moves on graph paper.
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HOW TO PLAY LIFE
Step 1. Choose your initial configuration by marking all live or full cells with an '0' (a bit). Note that you are free to choose any pattern desired for this beginning or zero generation. After this, the pattern is governed by Conway's rules.
Step 2. Scan* the pattern and mark all birth cells (i.e., those empty cells with exactly three neighbors containing a bit) with a '.' (a dot).
- scanning can be done by either or both (for double check) of these methods:
Method a. scan each empty cell of every row or column passing through and adjacent to the pattern.
Method b. scan each empty cell immediately around the pattern and within the pattern.
Step 3. Check each bit for the possibility of death (those with other than two or three neighbors containing a bit) and mark over the '0' with an 'X'.
Step 4. Copy all '0' and '.' to a new area or page for the next generation. You will now have the first generation in the Life history of your initial pattern. Go back to Step 2.
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Class E, Evolutionaries, Exercises, Et cetera . . .
The reader is invited to discover the fate of the two L's (a below), the string of seven bits (b), the dented row of bits (c), and the bits and block (d). The outcome of these exercises given on page six illustrate the common classes of object types that we have defined previously in LIFELINE.
Class I, Still Lifes and Stable Forms . . .
In the last newsletter I requested all known 10 and 11-bit still life objects. This seemingly 'simple' request is apparently more difficult than first imagined. While generalizing Class I structures, I found a mere nine-bit still life that had not been previously reported. Those heretofore known are shown below. Additional investigation then yielded even two more still lifes bringing the new total to ten different objects. Question 5.2: Can you discover any of these?
Class II, Oscillators . . .
The objects shown on the cover page of LIFELINE Number Five are but a small sampling of the many new discoveries made and sent in by David Buckingham, Mark Niemiec, and Peter Raynham of Sarnia, Ontario, Canada. They include several objects with periods never before reported. However, the most amazing aspect of this collection beside the periods (incidentally all eight are different) is the fact that they were all discovered manually. This should be a refreshing contrast to many readers the writer included who stared in awe at the cover features on the two previous issues of LIFELINE which obviously could never have been constructed or discovered without an excellent computer resource. Since each of the objects shown on the cover are easy to track I will leave for the reader the enjoyment of determining their periods. Hint: as a collection, the exact arrangment as shown on the cover will reappear again only after 2,520 generations! I will have more discoveries to report from this group in future issues of LIFELINE.
Class III, Spaceships and Pure Glider Generators . . .
The Curious 3-1-8 by Curt Gibson of New York, N.Y. and Robert Bison of Hopewell Jct., N.Y.
|Gibson's sparse 3-1-8 becomes a
glider heading southeast in 16.
|Bison's dense 3-1-8 (a duodecomino)|
becomes a glider heading southwest
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Reader Article . . .
The Period 12 'Line·Block' Oscillator by Edward Fitzgerald, David Lawson, and Tad Marshall of Irvington, N.Y.
An oscillator of period twelve has been discovered which exists on a 4x12 torus. The oscillator consists of a line and a block, and interestingly enough it is the only possible oscillator of its type which can exist on a torus of the size specified. It's twelve states are shown in the acconpianing illustration. I have taken as the primary state the one in which the line and the block are seperated in one direction by 2 spaces and in the other by 7 (the 2/7 state). In the second generation the line and block are in the 4/5 state, in Gen. 6 the oscillator is in the 8/1 state, and in Gen. 8 it is in the 6/3 state. Since the line and the block themselves occupy three horizontal spaces of the torus, the oscillator has all possible seperations of the line and the block, l.e. 1,2,3,4,5,6,7 and 8. Since a torus can be considered analagous with an agar, the line-block oscillator can be considered as an agar oscillator, and, with the addition of a properly spaced block on the opposite side of the line, it can exist on a cylinder. A cylinder is analogous with a wick, thus giving the line-block oscillator a wick form as well.
Excursions Into Other Universes . . .
|An Alien Spaceship From The Universe of '3-4' Life by Rici Liknaitzky
and The Other Hackers from the A.I.Lab at M.I.T.
|Lifecomic by Traw|
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|Answers to Reader Exercises 5.1:||Answers to Question 5.2:|
|a. The two L's rearrange themselves in the fifth generation
then die five generations later.
b. The string of seven bits evolves into a large S-shape
c. The dented row of bits forms the beautiful CP 48-56-72
d. The bits and block create a single glider headed
|Three new nine-bit still lifes|
.establishment of permanent newsletter departments
.some more eater-bound oscillators
.'Research in Occult Symbology' - a reader article
.Moore's garden of eden proof
.summary of answers to LIFESAVER questionnaire
.'Evolution' - a reader article
.more from Buckingham's Combine
.'BATTLEFIELD' - a new board game
.a bibliography of other newsletters devoted to
.Thompson has now tracked and/or tabulated
over 19,000 patterns! He
estimates there are about 68,000
different spatially-connected seven-bit
.There are 71 different two-glider
collisions (right angle and head-on)
which have all been tracked.
.LIFELINE Numbers Six and Seven will
be mailed In October and November.
|Reader Brief . . .||Reader Brief . . .|
|Don Woods of Natick, Mass. notes that:
8 squares form 8 square
|Charles L. Corderman of Westborough, Mass. notes that: |
including 13 gliders but
that the remainder of the final
census is not the same as the acorn!
LIFELINE EDITORIAL BOARD
Editor-in-chief: Robert T. Wainwright
Associate Editors: Names and addresses yet to be determined pending
response from LIFESAVER.
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There are many geographic concentrations of 'Lifenthusiasts'. For example, in the greater Boston area alone there_are 27 readers. Does the idea of form- ing a local group in your area for participation in Life activities appeal?
No[ ] Maybe it depends [ ] Yes[ ] for_ _ _ _ _ _ _ _ _ activities
This group might center around an installation with good computing capabili- ties. For instance, a university or research center with a graphical display device. Could/would you be able to offer such a facility to a local group?
No[ ] Maybe it depends [ ] Yes [ ] (explain)
In addition to local activities, such a group or even an individual could provide input to LIFELINE on a regular basis by reporting on their own ac- complishments. Whether acting as an associate editor for such a group or by contributing to one does this idea appeal to you?
No [ ] Maybe it depends [ ] Yes[ ] contributing Yes[ ] assoc.editor
Independent of any computer resources at your disposal, would you be inter- ested in contacting others in your area and starting a group if provided with an address list of all readers near you?
No [ ] Maybe [ ] Yes[ ] my phone number is: _ _ _-_ _ _-_ _ _
As interesting as Life is, there is a real gap in the spectrum of resources available to 'play' or investigate its mysteries. As the return questionnaire from May confirmed, the readership is definitely divided into two separate groups with large differences in exploratory capability. The 'Life-Club' concept would vastly improve this situation. More interestingly, a small keyboard device which can compute and display Life on an ordinary TV set will very probably be made available. If such a device were now available what is the maximum price (within your own reason) that you would be willing to pay?
$20 [ ] $50 [ ] $100 [ ] $200 [ ] $500 [ ] $1000 [ ] Other _ _ _ _ _ _ _
In order to just cover printing and mailing costs, the regular annual (4 lssue) subscription rate for LIFELINE will be two dollars for U.S. and Canada readers, one pound for U.K. readers, and three dollars (or the approx. equivalent) for all other foreign readers. If you are interested in participating in LIFELINE's endevours please indicate this by completing and returning LIFESAVER now. Although LIFELINE will continue to be primarily devoted to Life and related subjects, its actual format and specific content will evolve as other readers begin to take more of an active part in writing and editing. with this in mind, are you interested in subscribing as a:
[ ] Regular member (nov enclosing payment)
[ ] Participating member (will contribute to newsletter)
[ ] Other (explain)
With regard to'other', perhaps there are other means of exchange particular to your specific resources.
PLEASE NOTE: LIFELINE Numbers Six and Seven will be published in October and November so that we can be back on schedule with No.8 in December!
DON'T FORGET TO INCLUDE YOUR CORRECT NAME AND ADDRESS AND ZIP! (please print)