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## Crawlers

For discussion of specific patterns or specific families of patterns, both newly-discovered and well-known.

### Re: Crawlers

AforAmpere wrote:I also can't find a 1G reaction to get the block in the right spot.

I mean a reaction with the LoM before it settles into the blocks on the left hand side.

And for the reflection, I was thinking of something like this:
`x = 81, y = 173, rule = LifeHistory2C\$2C3\$.2C\$.2C16.2A\$19.2A22\$2C\$2C3\$.2C\$.2C16.2A\$19.2A10\$79.2C\$79.2C3\$78.2C\$60.2A16.2C\$60.2A6\$2C\$2C3\$.2C\$.2C16.2A\$19.2A10\$79.2C\$79.2C3\$78.2C\$60.2A16.2C\$60.2A6\$2C\$2C3\$.2C\$.2C16.2A\$19.2A10\$79.2C\$79.2C3\$78.2C\$60.2A16.2C\$60.2A6\$2C\$2C3\$.2C\$.2C16.2A\$19.2A8\$11.A\$10.3A\$10.A.2A65.2C\$79.2C3\$78.2C\$60.2A16.2C\$60.2A22\$79.2C\$79.2C3\$78.2C\$60.2C16.2C\$60.2C8\$69.A\$68.3A\$67.2A.A!`

This reaction in particular doesn't give what we wanted, but you get the idea.

Rhombic

Posts: 754
Joined: June 1st, 2013, 5:41 pm

### Re: Crawlers

Rhombic wrote:And for the reflection, I was thinking of something like this:

The problem there is that the two tracks would eventually converge.
A base-2 ruler for all your measuring needs in CGOL:
`32b32o\$16b16o16b16o\$8b8o8b8o8b8o8b8o\$4b4o4b4o4b4o4b4o4b4o4b4o4b4o4b4o\$2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o2b2o\$bobobobobobobobobobobobobobobobobobobobobobobobobobobobobobobobo`
Gamedziner

Posts: 356
Joined: May 30th, 2016, 8:47 pm

### Re: Crawlers

Gamedziner wrote:The problem there is that the two tracks would eventually converge.

Well yeah, but isn't that how 31/240 etc work? you set up something to delete the last B-heptomino and connect a synthesis at a translation.
What qualifies as a promising reaction otherwise? We've probably found most of the single transparent still-life mechanisms (and otherwise this should have been done by now!! someone get on with C++, I'll donate my CPU)

Rhombic

Posts: 754
Joined: June 1st, 2013, 5:41 pm

### Re: Crawlers

Rhombic wrote:
Gamedziner wrote:The problem there is that the two tracks would eventually converge.

Well yeah, but isn't that how 31/240 etc work? you set up something to delete the last B-heptomino and connect a synthesis at a translation.

Your understanding of the prior work seems wrong, the crawlers are not deleted in any of the fast ships. The only one where an crawler seems to be deleted and resynthesized is the HBK, since the glider is destroyed and rebuilt. But I argue that the glider isn't even the "crawler" in the HBK, but rather the "crawlee."

A reaction shifting two tracks relative to one another isn't a dealbreaker, but it makes things harder for sure. You probably want to work with non-mirrored track pairs in trying to patch this up.

What qualifies as a promising reaction?

The ideal is the following. Have some pair of objects at t=0, let's call them C1 and C2. C1 is the crawler and can be arbitrarily complex, C2 the "crawlee" and needs to be a regular pattern (periodic or periodic-with-offset like a spaceship).

At time t=T, the universe again consists of C1 and C2, but C1 is displaced by vector V1 with components (A1, B1), and C2 displaced by V2 with components (A2, B2), and possibly advanced by G2 generations. Examples:

C1 = Pi
T = 45
V1 = (0, 17)
V2 = (0, -11)
G2 = 1
`x = 5, y = 17, rule = B3/S232bo\$2bo\$2bo12\$b3o\$o3bo\$2ob2o!`

C1 = Herschel
C2 = Block
T = 240
V1 = (0, 31)
V2 = (0, -22) or (-8, -4)
G2 = 0
Extra block and 2 gliders
`x = 10, y = 26, rule = B3/S238b2o\$8b2o22\$3o\$bo\$b3o!`

C1 = Herschel
C2 = Glider
T = 79
V1 = (23, 5)
V2 = (-27, -29)
G2 = 1
Extra glider
`x = 16, y = 18, rule = B3/S2315bo\$13b2o\$14b2o13\$3o\$bo\$b3o!`

C1 = Herschel
C2 = Glider
T = 72
V1 = (27, 1)
V2 = (-22, -38)
G2 = 0
Extra bunch of junk
`x = 14, y = 28, rule = B3/S2311bobo\$11b2o\$12bo23\$3o\$bo\$b3o!`

C1 = Half-Bakery
C2 = Glider
T = Anything more than 62
V1 = (6,3)
V2, G2 = Depends on T
`x = 16, y = 14, rule = B3/S23b2o\$o2bo\$bobo\$2bob2o\$3bo2bo\$4bobo\$5bo5\$13b2o\$13bobo\$13bo!`

In all of these cases, the spaceship speed is V1 divided by T. C1 objects are not created or destroyed at any point in the ship. The challenge is for objects of type C2 to be created at the front and destroyed at the back. The displacement and phase shift of the second object simply tells where the next crawler must be for the reaction to repeat, which is important for the construction aspect but doesn't say much about the possibility/impossibility of the ship except for maybe giving a good idea about coset problems.

If C1 reappears but C2 is incompletely formed, it is usually really hard to do anything to salvage the crawler. If there is way too much junk, it's again usually really hard. If there is no junk at all, it depends on whether anything good comes out of rubbing multiple copies together.

If the goal is to dig up a ton of promising reactions, going into slightly more complex Cs would be a way to go. Either use multiple still lives and oscillators together as C2 (but bear in mind that the chance of having C2 fully rebuilt at any later T is way lower), or more exotic C1 (combinations of active objects, or just more odd ones).
Physics: sophistication from simplicity.

biggiemac

Posts: 502
Joined: September 17th, 2014, 12:21 am
Location: California, USA

### Re: Crawlers

By doubling muzik's crawler you get usable variations perhaps.

The second crawler restores the position of the blocks.
`x = 64, y = 387, rule = B3/S23obo\$obo\$3o14b2o\$17b2o2\$4b2o\$4b2o13\$17bo\$15bo2bo\$14bo\$17bo4bo\$17b2o2bobo\$6b2o2b2o2bob2o4bo\$6b2o2b2o3b2o3bo8\$24b3o\$24bobo\$23bobo3\$22bobo\$22bobo\$22b3o3\$8b2o16b2o\$8b2o16b2o18\$10b2o16b2o\$10b2o16b2o18\$12b2o16b2o\$12b2o16b2o18\$14b2o16b2o\$14b2o16b2o18\$16b2o16b2o\$16b2o16b2o18\$18b2o16b2o\$18b2o16b2o18\$20b2o16b2o\$20b2o16b2o18\$22b2o16b2o\$22b2o16b2o18\$24b2o16b2o\$24b2o16b2o18\$26b2o16b2o\$26b2o16b2o18\$28b2o16b2o\$28b2o16b2o18\$30b2o16b2o\$30b2o16b2o18\$32b2o16b2o\$32b2o16b2o18\$34b2o16b2o\$34b2o16b2o18\$36b2o16b2o\$36b2o16b2o18\$38b2o16b2o\$38b2o16b2o18\$40b2o16b2o\$40b2o16b2o18\$42b2o16b2o\$42b2o16b2o18\$44b2o16b2o\$44b2o16b2o!`

This produces gliders.
`x = 38, y = 219, rule = B3/S2310bobo\$10bobo\$10b3o3\$14b2o\$14b2o2\$2o\$2o15\$16b2o\$16b2o2\$2b2o\$2b2o15\$18b2o\$18b2o2\$4b2o\$4b2o15\$20b2o\$20b2o2\$6b2o\$6b2o15\$22b2o\$22b2o2\$8b2o\$8b2o15\$24b2o\$24b2o2\$10b2o\$10b2o15\$26b2o\$26b2o2\$12b2o\$12b2o15\$28b2o\$28b2o2\$14b2o\$14b2o15\$30b2o\$30b2o2\$16b2o\$16b2o15\$32b2o\$32b2o2\$18b2o\$18b2o15\$34b2o\$34b2o2\$20b2o\$20b2o15\$36b2o\$36b2o2\$22b2o\$22b2o!`

2 rows of blocks are fused to 1.
`x = 42, y = 239, rule = B3/S2312bobo\$12bobo\$12b3o3\$16b2o\$16b2o3\$2o\$2o14\$18b2o\$18b2o3\$2b2o\$2b2o14\$20b2o\$20b2o3\$4b2o\$4b2o14\$22b2o\$22b2o3\$6b2o\$6b2o14\$24b2o\$24b2o3\$8b2o\$8b2o14\$26b2o\$26b2o3\$10b2o\$10b2o14\$28b2o\$28b2o3\$12b2o\$12b2o14\$30b2o\$30b2o3\$14b2o\$14b2o14\$32b2o\$32b2o3\$16b2o\$16b2o14\$34b2o\$34b2o3\$18b2o\$18b2o14\$36b2o\$36b2o3\$20b2o\$20b2o14\$38b2o\$38b2o3\$22b2o\$22b2o14\$40b2o\$40b2o3\$24b2o\$24b2o!`
christoph r.

Posts: 40
Joined: March 24th, 2016, 2:55 pm
Location: Germany

### Re: Crawlers

Thank you for this clear explanation with examples! A couple of ideas:

1) Could you add the (obvious) space ships based on the repective direction?

2) I miss the (13,1)c/31 reaction

3) How do the reactions used in the caterloopillar fit in the picture?

4) Glider duplicating *WSS fleets would be another (hard to control) type of reaction wher both reaction partners move
HartmutHolzwart

Posts: 377
Joined: June 27th, 2009, 10:58 am
Location: Germany

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