Cellular automata collider
Spaceship in the Single Rotation rule and similar reversible cellular automata often have very long periods, making manual enumeration of all possible interactions problematic.
I made a "collider" script that automatically enumerates all possible interactions of 2 patterns.
Here are some results of colliding 5 lightest spaceships (A..F) with simple patterns:
Single cell
2x2 block
2x4 block