Moving sawtooth is an orthogonal sawtooth spaceship with expansion factor 3 that was found by David Bell on July 10, 2005. Its minimum infinite repeating population is 1239, and it is notable because it is it the first sawtooth spaceship.
The pattern can be seen below. It works by using the output of c/3 rakes to ignite the blinkers from a blinker puffer 1 (which moves at c/2), with the number of blinkers to be consumed growing in each cycle. Once ignited, the blinker fuse burns at 2c/3.
The number of alive cells plotted versus the number of elapsed generations roughly forms an ever-increasing sawtooth graph
On June 10, 2025, David Bell constructed a moving sawtooth in which two symmetrically placed c/12 diagonal period 96 backward rakes each suppress gliders from the other rake. It is the record minimum population moving sawtooth, with a repeating minimum population of 540.[1]
#C A moving sawtooth with a repeating minimum population of 540.
#C This uses two symmetrically placed diagonal c/12 period 96
#C backward rakes whose output gliders suppress gliders from
#C the other rake.
#C David I. Bell, 11 June 2025
x = 136, y = 122
58bo$57bobo$56bo3bo13b3o$56bo3bo8bo$56bobob3o4boob3o$57boobobbo5boboo$
61bobo8bo$61boo11bobbo5boo$74b3o6boo$46bo$46bo$46bo$49boo$49boo12boo$
44bo3b3o11boo$45b3o15bo$46bo15b3o$45boo15b3o23boo$45b3o16bo22b4o$47bo
14bobbo20bo3bo$45bo16b3o26bo$47bo15bo27bo$45b3o44bo$$128boo$128boo3$
60bobo$60bobbo56bo$60bobbo56bo$60bo3bo52b4o$50boo9bobo52bobbo11bo$50b
oo10bo53bo13boo$116bobbo9bo3bo$117boo11boobbo$135bo$132bobo$133bo$133b
o$58boo73boo$58boo73boo4$132bo$52b3o76bo$52b3o44bo31boo$53bo40bo5bo32b
o$23b3o28boo38bo6bo30b3o$23b3o29bo39bobobbo31b3o$24bo29bo67boo$25boo
66b3o17boo7boo$26bo66b3o17boo$25bo14boo51bobo13bo$40boo10boo39bobo12b
oo$52boo39boboo10bo3bo13bo$53bo18bo20bobbo11boobbo11b3o$23boo46bo22bob
o16bo$12bo10boo47bo20boo15bobo4bobo4bo3bo$7bobbobobbo3bo4bo70bo15bo4b
5oboo4bo$7bo4boob5o4bo15bo70bo4bo3bobbobobbo$7bo3bo4bobo4bobo15boo20bo
47boo10bo$22bo16bobo22bo46boo$9b3o11bobboo11bobbo20bo18bo$10bo13bo3bo
10boobo39boo$26boo12bobo39boo10boo$26bo13bobo51boo14bo$21boo17b3o66bo$
12boo7boo17b3o66boo$12boo67bo29bo$b3o31bobbobo39bo29b3o$b3o30bo6bo38b
oo28b3o$bbo32bo5bo40bo$3boo31bo44b3o$4bo76b3o$3bo4$boo73boo$boo73boo$
bbo$bbo$bobo$o$bobboo11boo$bbo3bo9bobbo$4boo13bo53bo10boo$4bo11bobbo
52bobo9boo$15b4o52bo3bo$15bo56bobbo$15bo56bobbo$73bobo3$6boo$6boo$$43b
o44b3o$44bo27bo15bo$44bo26b3o16bo$45bo3bo20bobbo14bo$45b4o22bo16b3o$
46boo23b3o15boo$71b3o15bo$72bo15b3o$72boo11b3o3bo$71boo12boo$85boo$89b
o$89bo$89bo$51boo6b3o$51boo5bobbo11boo$63bo8bobo$63boobo5bobboboo$63b
3oboo4b3obobo$66bo8bo3bo$59b3o13bo3bo$76bobo$77bo!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
#C [[ THUMBSIZE 2 ZOOM 6 WIDTH 900 HEIGHT 900 GRID ]]
The number of alive cells plotted versus the number of elapsed generations roughly forms an ever-increasing sawtooth graph
