(25.12.2013) Добра подобрена реализация на Коледната идея на Кенет. Добре дошъл на Henry Tanner от Финландия!

1 Kf3 Sc7 2 Ke4 Gf4 3 Kxf4=rG+ Sd5#

1 b5 Gc6 2 Kf3 Gc6-g2 3 Kxg2=rG Sf4#

Protean chess: the pieces transforms into the type of pieces they capture. When a king captures it retains its royal properties. A captured pawn continues in the same direction, so a captured black pawn becomes a backward-moving white pawn.

Grasshopper: Hops on Queen lines over any one unit (the hurdle) to the next square beyond.