# Lifeline Volume 7

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Lifeline Volume 7
Published in November 1972
Preceded by Volume 6
Succeeded by Volume 8
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

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Number 7                                               NOVEMBER 1972```
• Editor and Publisher: Robert T. Wainwright

#### Page 1

In LIFELINE Number Six, I described two of Conway's conjectures regarding Garden of Eden configurations. JHC himself is offering \$50 to the first person to settle either conjecture. To date no one has submitted a proof for either of these challenges and they still remain. I would now like to present another challenge which Conway lists as one of Life's 'problems'.

The Immovable Object Problem: is it possible to design an object (i.e. a pattern or configuration) inside a 1001 by 1001 square (say) which will protect the central cell (within the square) for all time against any invasion from outside? In other words, the state of the central cell must never change whatever we put outside the 1001-square.

Editor's note (EN): think of this as a game:

 You put your clever ob-ject in here, so that the central cell will never change its state. I put whatever Ilike out here, and try to make thecentral cell change

Fifty dollars for this as well. All decisions about validity of proofs to be Conway's alone. Now let us consider the related problem which is:

The Irresistible Force Problem: is it possible to design an object, that is, some kind of spaceship with a similar sort of property? This is easily proved impossible / just shoot two at each other! As Conway points out, you really do not need both an immovable object and an irresistible force to get a paradox / an irresistible force will do, if you opppose it to a copy of itself.