Keys "s"=save "l"=load "b"=back once
This very popular version, the knights cannot capture or be captured, and give their power of movement to any friendly piece, except the king, which they defend.
This does not enable a pawn to move to the first or last rank, or to check a king which is there. The inventor is Mannis Charosh around 1972.
Thanks to Dale Hawthorn for help with the debugging (March 2006).
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!