switch engine

plural switch engines

1. A switcher or shunter: a railroad locomotive used for shunting.
2. cellular automataA 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 May 17, David Moews, “Life questions”, in comp.theory.cell-automata (Usenet)

   2 more examples

   He did this by placing a large number of switch engines together so as to eliminate all debris. His original ship required 13 switch engines, but his smaller one given here only uses 10 of them.

   1992 August 13, David Bell, “Spaceships in Conway's Life (Part 1)”, in comp.theory.cell-automata (Usenet)

   The average random Life pattern settles down instead of exploding (if you ignore output gliders and spaceships). There are exceptional quadratic-growth cases, mostly involving switch engines, but most random patterns affect only their immediate area.

   2007 May 12, Dave Greene, “Wanted: 2D CA, "as complex" but "denser" than Life”, in comp.theory.cell-automata (Usenet)