An html version of rookcorners.cql

; rookcorners.cql can be downloaded here.
; Find all games in which the same rook visits all four corners of the board.

(match
 :pgn heijden.pgn
 :output out.pgn
 :forany rook [rR] ; loop over the possible rooks
 (position $rook[a1]) 
 (position $rook[h1])
 (position $rook[h8])
 (position $rook[a8])
 )