Goldtiger997 wrote:mniemiec wrote:All but one of the above syntheses (#4) improve the state of the art. Congratulations! 6 of them can be slightly improved, by tightening up initial still-life synthesis and/or final cleanup:

Thanks. I'm not currently trying to optimize the syntheses I make, just make them below 15 gliders. I stop improving them once they're below 15 gliders.

Here are 5 15-bit still lifes with a price of less than 1 glider/bit.

15.1319 (15G->13G):

`x = 184, y = 36, rule = B3/S23`

8$21bobo$22b2o$22bo3$10bo77bo$11b2o41bobo21bo10b2o7bo19bo29bo19bo$10b

2o43b2o19b3o9b2o6b3o17b3o27b3o17b3o$55bo19bo19bo19bo29bo19bo$75b2o18b

2o19bo29bo19bo$52b3o60b2o28b2o20bo$42b2o10bo7b2o18b2o18b2o18b2o28b2o

14bo3b2o$38b2o2bo10bo4b2o2bo15b2o2bo9b2o4b2o2bo15b2o2bo15bo9b2o2bo16bo

2bo$28b3o7bobobo15bobobo15bobobo8bobo4bobobo15bobobo13bobo9bobobo17bob

o$16bo11bo12bo19bo19bo11bo7bo19bo15b2o2b2o8bo19bo$17b2o10bo65b2o43bobo

$16b2o77bobo44bo3b2o$95bo49b2o$147bo$16b3o$18bo$17bo!

15.1317 (16G->11G):

`x = 99, y = 30, rule = B3/S23`

6$23bo$24bo$22b3o42bo$68b2o$30bo36b2o$29bo44b2o$29b3o40bobobo$18bobo

49bobobo$19b2o50b2o16b2o$13b2o4bo26b2o18b2o18b2o2bo$12bobo30bobo17bobo

17bob2o$14bo5b2o22bo19bo6bo12bo$21b2o20bo19bo5b2o12bo$20bo21bo19bo7b2o

10bo$39bobo17bobo17bobo$39b2o18b2o18b2o$71b2o$15b2o54bobo$16b2o53bo$

15bo!

15.1287 (16G->11G):

`x = 167, y = 143, rule = B3/S23`

8bo$9bo$7b3o8$o$b2o$2o40$137bo$136bo$136b3o$148bo$137b3o7bo$139bo2bobo

2b3o$138bo4b2o14b2o$134bo8bo15bo$134b2o25bo$120b2o11bobo4b2o18b2o$120b

o19bo19bo$121bo19bo19bo$122bo2b2o15bo2b2o15bo2b2o$123bo2bo16bo2bo16bo

2bo$124b2o18b2o18b2o15$36b2o$37b2o$36bo13b2o$49b2o$51bo$47b2o$46bobo$

48bo52$109bo$108b2o$108bobo!

15.1253 (16G->12G):

`x = 171, y = 25, rule = B3/S23`

7$17bobo24bo19bo19bo19bo19bo19bo19bo$18b2o23bobo17bobo17bobo17bobo17bo

bo17bobo17bobo$18bo24b2o18b2o18b2o11bo6b2o18b2o18b2o18b2o$23bobo15b2o

18b2o18b2o14bo3b2o18b2o18b2o18b2o$23b2o17bo19bo19bo12b3o4bo10bo3b2o3bo

10bo3b2o3bo14b2o3bo$17b3o4bo16bo19bo19bo9b3o7bo10bobo3bo2bo10bobo3bo2b

o16bo2bo$19bo20bo19bo19bo12bo6bo12bo4bobo12bo4bobo17bobo$18bo21b2o18b

2o14b2o2b2o10bo3b2o2b2o17bo10b2o7bo19bo$76bo19bo32bobo$56b2o16bobo17bo

bo17b2o15bo2b2o$55b2o17b2o18b2o4b3o11b2o18b2o$7b3o13b2o27b2o3bo44bo$9b

o13bobo25bobo47bo3bo$8bo14bo29bo50b2o$104bobo!

15.1215 (16G->14G):

`x = 89, y = 36, rule = B3/S23`

29bo$29bobo$29b2o6$9bo$9bobo$9b2o2b3o$13bo$14bo4$12b3o$12bo$13bo3$41bo

b2o16bob2o16bob2o$41b2obo16b2obo16b2obo$45b2o18b2o18b2o$46bo19bo19bo$

45bo19bo19bo$45b2o18b2o18bobo$bo58bo13bo11bobo$b2o58b2o6b2o2bo13bo$obo

13b3o5b2o34b2o6b2o3b3o$16bo6b2o45bo6b3o$17bo7bo36bo14bo$62b2o8b2o4bo$

61bobo4b2o2bobo$69b2obo$68bo!

The challenge proposed by the Goldtiger997, very interesting. According to my data from the 15-bit still lifes have 51 cost equal to 1 glider/bit and 93 cost great 1 glider/bit. The highest cost at 15.619 (33G).

Bob Shemyakin