Mutant Effect

[drc]

I have noticed a strange effect in CAs like Day&Night. Take a look at the snail, broken up into halves:

Code: Select all

x = 129, y = 26, rule = B3678/S34678
2o18b3o17b3o17bobo17b3o17b3o17b3o$bo20bo19bo17bobo17bo19bo19bobo$bo18b
3o17b3o17b3o17b3o17b2o20bo$bo18bo21bo19bo19bo17bobo19bo$3o17b3o17b3o
19bo17b3o17b3o19bo3$4bo17bobo18bo19bobo18bo18bobo17bobo$3b2obo14bo2bo
16bob2o16b3o2bo14b2obobo14b7o16b4o$2b5o14b6o13b6o15b6o13bob6o13bob5o
12b7obo$3b2obo14bo2bo16bob2o16b3o2bo14b2obobo14b7o16b4o$4bo17bobo18bo
19bobo18bo18bobo17bobo3$4bo17bobo18bo19bobo18bo20bo18b2o$o2b2obo14bo2b
o15b2ob2o16b3o2bo14bo2bobo17b4o13b2o2b3o$2b5o13b7o13b6o14bob5o14b7o12b
8o15b4obo$o2b2obo14bo2bo15b2ob2o16b3o2bo14bo2bobo17b4o13b2o2b3o$4bo17b
obo18bo19bobo18bo20bo18b2o3$3o17b3o15bob3o17bobo15bob3o15bob3o17bobobo
$obo17bobo15bobobo17bobo15bo3bo15bo3bo17bobobo$bo18b3o15bobobo17bobo
15bob3o15bob3o17bob3o$obo19bo15bobobo17bobo15bobo17bo3bo17bo3bo$3o19bo
15bob3o17bobo15bob3o15bob3o17bo3bo!

Notice anything? That's right, the front halves (and mostly the entire ship) look extremely similar. The same thing happens in B2/S34:

Code: Select all

x = 13, y = 29, rule = B2/S34H
2o8b2o$bo10bo$bo9bo$bo8bo$3o8b2o3$10bo$2o$10bobo$b2o$12bo6$10bo$2o$bo
9bo$b2o$12bo3$2o8bo$2bo7bobo$b2o8b2o$2bo9bo$2o10bo!

Has anybody observed this effect?

[Bullet51]

Maybe.

Code: Select all

x = 23, y = 25, rule = LifeHistory
4.2A12.2A$7.A.A4.A.A$4.A2.2A6.2A2.A$4.A14.A$6.A10.A$4.A14.A$3.2A14.2A
$3.3A12.3A$5.A12.A$5.A12.A2$5.2C10.2C$2.C.C9.C.C$2.C2.C8.C2.C$4.C11.C
$.2C10.2C2$2.2C2.C7.2C2.C$C6.C4.C6.C$.2C4.C5.2C4.C$.C.C9.C.C$4.2C.C8.
2C.C$5.C.C.2C6.C.C.2C$8.3C9.3C$9.C11.C!

[BlinkerSpawn]

This is because almost all spaceships are like front-wheel drive vehicles: a reaction pulls it forward, and everything behind keeps the ship stable.
There can only be so many reactions that can be stabilized and run at a certain speed, so a lot of ships at a given speed will look alike.
Just take a look at the c/4 orthogonal collection in Golly and ask yourself how many traffic-light haslers there are.

[fluffykitty]

Similar things in 123456-3_234-23_b:

Code: Select all

x = 7, y = 21, rule = 123456-3_234-23_b
2$4.2B$2.2A2B$.3A2B$2.2A2B$3.2B9$3.2B$2.2A2B$.3A2B$2.2A2B$3.2B!

[SuperSupermario24]

Just take a look at the c/4 orthogonal collection in Golly and ask yourself how many traffic-light haslers there are.

I thought of the glider-pulled c/4 diagonal ones.