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Spiders, spaceships and syntheses

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Spiders, spaceships and syntheses

Postby calcyman » August 27th, 2009, 3:03 am

Using just spiders and MWSSes, it's possible to synthesise the three *PPS spaceships:

x = 239, y = 46, rule = B3/S23
62b3o25b3o53b3o25b3o53b3o$61b5o23b5o51b5o23b5o51b5o$60boob3o23b3oboo
49boob3o23b3oboo49boob3o$8boo51boo29boo51boo29boo51boo$5b3oboo$5b5o$6b
3o11$46bo5boo5boo5bo21bo5boo5boo5bo21bo5boo5boo5bo21bo5boo5boo5bo21bo
5boo5boo5bo$44bobbooboobbo3bobbooboobbo17bobbooboobbo3bobbooboobbo17bo
bbooboobbo3bobbooboobbo17bobbooboobbo3bobbooboobbo17bobbooboobbo3bobb
ooboobbo$4bo5boo5boo5bo17b3o4bobo3bobo3bobo4b3o13b3o4bobo3bobo3bobo4b
3o13b3o4bobo3bobo3bobo4b3o13b3o4bobo3bobo3bobo4b3o13b3o4bobo3bobo3bobo
4b3o$bbobbooboobbo3bobbooboobbo15boobbobb3oboo3boob3obbobboo13boobbobb
3oboo3boob3obbobboo13boobbobb3oboo3boob3obbobboo13boobbobb3oboo3boob3o
bbobboo13boobbobb3oboo3boob3obbobboo$3o4bobo3bobo3bobo4b3o13b3obb3o4bo
3bo4b3obb3o13b3obb3o4bo3bo4b3obb3o13b3obb3o4bo3bo4b3obb3o13b3obb3o4bo
3bo4b3obb3o13b3obb3o4bo3bo4b3obb3o$oobbobb3oboo3boob3obbobboo14bobobbo
15bobbobo15bobobbo15bobbobo15bobobbo15bobbobo15bobobbo15bobbobo15bobo
bbo15bobbobo$3obb3o4bo3bo4b3obb3o15bo23bo17bo23bo17bo23bo17bo23bo17bo
23bo$bobobbo15bobbobo$bbo23bo15$201bo$200b3o$200boboo$201b3o$201b3o$
201boo!


However, there is currently no known way of synthesising the spider in the first place. In fact, the only spaceship speeds that can be synthesised are:

c/2 orthogonal
c/4 diagonal
2c/5 orthogonal
c/12 diagonal

I think that the next speed to go will be 2c/7, since the weekender is so small. Weekender predecessors have already been found, which looks promising.

The remaining speeds, which have no known synthesis, are:

c/3 orthogonal
c/4 orthogonal
c/5 orthogonal
c/6 orthogonal
2c/7 orthogonal
17c/45 orthogonal*
c/5 diagonal
c/6 diagonal


* The Caterpillar is actually very easy to construct, but the sheer size of it makes it inordinately tedious. In fact, all of the components of the Caterpillar are constantly removed and re-synthesised, apart from the pi heptominoes that crawl along the tracks. Pies can be synthesised from two gliders, anyway.


Of these speeds, the Caterpillar is the only purely engineered spaceship. Well done to Gabriel Nivasch, Jason Summers and David Bell!

You can read about the Caterpillar here:

http://www.yucs.org/~gnivasch/life/article_cat/index.html
What do you do with ill crystallographers? Take them to the mono-clinic!
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Re: Spiders, spaceships and syntheses

Postby Jason Summers » August 28th, 2009, 7:42 pm

calcyman wrote:I think that the next speed to go will be 2c/7, since the weekender is so small. Weekender predecessors have already been found, which looks promising.

I've never been able to make much headway in constructing a weekender. If there are any recent results in that direction that I might not know about, I'd like to see them.

I thought for a while that the c/3 "dart" was a better candidate, but the innocent looking pre-honeyfarm at the front turns out to be a big problem. There's just no way to attach one in that orientation.
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Re: Spiders, spaceships and syntheses

Postby calcyman » August 29th, 2009, 5:41 am

If there are any recent results in that direction that I might not know about, I'd like to see them.


Dave Greene sent me an e-mail message containing the following partial synthesis:

x = 22, y = 20, rule = B3/S23
2bo12bo$3b2o11b2o$2b2o11b2o2$6bo12bo$4b2o11b2o$5b2o11b2o3$4bob2o2b2o2b
2obo$5b3obo2bob3o$bo6b6o6bo$2bo2bob2o4b2obo2bo$obo2bobobo2bobobo2bobo$
o3bo3bo4bo3bo3bo$3bob4ob2ob4obo$bobob2o8b2obobo$2bo2bo2bo4bo2bo2bo2$6b
obo4bobo!


It shows how the bullet heptominoes could be fused to the body.

If I remember correctly, the 2c/5 ship is so constructible because it's based on a still life. Could that principle be used to yield new syntheses?
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Re: Spiders, spaceships and syntheses

Postby Jason Summers » August 31st, 2009, 10:35 pm

calcyman wrote:Dave Greene sent me an e-mail message containing the following partial synthesis:
...

The fact that a complicated predecessor like that exists doesn't really help, but finding a lot of them and watching them evolve is a good way to get clues about how to attack the problem.
If I remember correctly, the 2c/5 ship is so constructible because it's based on a still life. Could that principle be used to yield new syntheses?

Well, the center of one phase is a near still life:
..**..
.*..*.
**..**

I've tried propping it up like so:
....**....
**.*..*.**
*.**..**.*

and hitting the edges with random patterns in the hopes that something useful will happen. Didn't have much luck with that, though.
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Re: Spiders, spaceships and syntheses

Postby HartmutHolzwart » November 16th, 2009, 4:17 pm

would it be possible to use queen bee for the c/3 dart construction?
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Re: Spiders, spaceships and syntheses

Postby Axaj » November 16th, 2009, 9:43 pm

HartmutHolzwart wrote:would it be possible to use queen bee for the c/3 dart construction?


Maybe... It's probably worth a shot. I'm not too good with synthesis though, so someone else would have to try.
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Re: Spiders, spaceships and syntheses

Postby abiessu » December 29th, 2009, 12:22 am

I'm guessing that the construction of the front of the dart is already well-known:

x = 8, y = 13, rule = B3/S23
6$7bo$5b2o$6b2o$2b2o$bobo$3bo!


I thought I could get it close enough to a couple of loaves and then sort out how to 'fill in' the middle:

x = 31, y = 25, rule = B3/S23
10bo$8bobo$9b2o$23bo$14bo6b2o$12bobo7b2o$13b2o$20bo$20b2o$19bobo5$5bo$
5b2o$4bobo3$3o$2bo$bo$28b3o$28bo$29bo!


But I'm guessing this is some of what has been tried already...
x = 26, y = 26, rule = B3/S23
12b3o$11b5o$11b3ob2o$14b2o$18b2o2b4o$20b2o3bo$19bo5bo$24bo$19bo2bo$19b
2o$21bo$5bo7bo4bo4bo$6bo7bo9bo$o5bo2bo4bo4bo4bo$b6o3b5o5b5o2$18bobo$
17bo2bo$18bobo$18b2o$18b2ob5o$25bo$12b3o3bo6bo$11b5o3b2o3bo$11b3ob2o$
14b2o!
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