Circe = a captured unit will be reborn on (what is defined to be)
its starting square. If that square is occupied the unit is removed.
The starting square is obvious for the queen and both bishops.
For rook and knights that square is defined to be the one of two
possible ones with the same colour as the one they was captured on.
For pawns the square of origin is defined to be the relevant square
in the same file as the capture took place.
AntiCirce = the capturing unit will be reborn according to
the circe rules while the captured unit is removed from the board.
If the rebirth square is occupied the capture is illegal