+ "Pieces upside down": "Pieces upside down",
+ "Play at the same time (v1)": "Play at the same time (v1)",
+ "Play at the same time (v2)": "Play at the same time (v2)",
+ "Play more and more moves (v1)": "Play more and more moves (v1)",
+ "Play more and more moves (v2)": "Play more and more moves (v2)",
+ "Play opponent's pieces": "Play opponent's pieces",
+ "Powerful pieces": "Powerful pieces",
+ "Prolongated captures": "Prolongated captures",
+ "Promote into kings": "Promote into kings",
+ "Protect your pawns": "Protect your pawns",
+ "Push and pull": "Push and pull",
+ "Queen disguised as a pawn": "Queen disguised as a pawn",
+ "Queen versus pawns": "Queen versus pawns",
+ "Reach the last rank (v1)": "Reach the last rank (v1)",
+ "Reach the last rank (v2)": "Reach the last rank (v2)",
+ "Replace pieces": "Replace pieces",
+ "Reposition pieces": "Reposition pieces",