Keys "s"=save "l"=load "b"=back once
The four center squares rotate under certain conditions. This applet lets you try many different options. In the original version by AE Farebrother and WH Rawlings, the center squares along with any occupants made a quarter-turn clockwise whenever a piece entered it, moved within it, or left it.
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!