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What is his name ?

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Bruno Gilleta

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Dec 12, 1996, 3:00:00 AM12/12/96
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Hello !

I generated chance this pattern in Game of life by chance :

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

It behaves like a vacuum that cleans - - - - - lines.
Do you know how it is named and where to find similar ones ?

Thanks.
---
Bruno Gilleta.

Dean Hickerson

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Dec 16, 1996, 3:00:00 AM12/16/96
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Bruno Gilleta (gil...@lim.univ-mrs.fr) wrote:

The general names for such things are "wick" and "fuse". A "wick" is any
one dimensionally infinite pattern that's spatially and temporally periodic,
like the line of blinkers above. A "fuse" is a way for a wick to burn from
one end, leaving behind either empty space, as above, or something else, as
below, in which a line of beehives gets converted into blocks:

........................ooo.................
.o...o...o...o...o...oooo.o.................
o.o.o.o.o.o.o.o.o.o.o.o.o...................
o.o.o.o.o.o.o.o.o.o.o.o.oo.o................
.o...o...o...o...o...ooooo.o.o..............
........................oo.o.o....oo......oo
..........................o.......oo......oo

The particular fuse that you found ("blinker fuse") has been important in
several constructions, including this beautiful period 240 puffer found by
David Bell in 1992:

..............ooo............
.............ooooo...........
............oo.ooo...........
ooooo........oo..............
o....o.......................
o............................
.o...o.......................
...o.........................
..ooo......................oo
.oooo...............oo.o..ooo
oo.oo..............o.o.ooooo.
.oo....ooo.ooo.ooo.o.........
...................o.o.ooooo.
....................oo.o..ooo
...........................oo
.............................
..oooooo.....................
..o.....o....................
..o..........................
...o....o....oo..............
.....oo.....oo.ooo...........
.............ooooo...........
..............ooo............

The front of this is a p8 blinker puffer found by Robert Wainwright. When
the fuse catches up with the puffer, it produces a large spark, while the
puffer continues making blinkers. The trailing middleweight spaceships
convert the spark into a pair of pi-heptominos, which start the line of
blinkers burning again, while leaving behind a pair of blocks. David Bell
produced puffers of many larger periods as well, using more complicated
ways of restarting the burning. Some of these are described in his article
on spaceships, at:
http://research.Germany.EU.net:8080/~joke/rsc/ships_toc.html

For another application of the same fuse, see "hacksaw" in Paul Callahan's
Life web page:
http://www.cs.jhu.edu/~callahan/patterns/cat5.html
This is one of several known "sawtooth" patterns, in which the population
is unbounded but does not tend to infinity.

Dean Hickerson
de...@ucdmath.ucdavis.edu

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