cavitty = cellular automata visualizations in the terminal, yo!
gem install cavitty, then cavitty -h for usage.
Folks like to show off their terminal color schemes in all sorts of ways. This is option n + 1. Also, some (but not most) of the elementary cellular automatons are just fun to watch evolve. This is best done on a terminal emulator that supports changing the font size on the fly, since zooming way out is usually necessary to get the full effect.