switch engine

noun2

1. •
   A switcher or shunter: a railroad locomotive used for shunting.
2. •
   A particular methuselah in Conway's Game of Life that temporarily exhibits glide reflection symmetry while leaving debris behind, allowing for the construction of spaceships, puffers, and rakes.

   • 2. Is it possible to make the switch engine leave debris other than the normal 8 blocks/288 generations? — 1990