rook-corners-rotate-with-range.cql

// Download rook-corners-rotate-with-range.cql
// PGN output when run on sample.pgn

/********
look for rook visiting the four corners
This uses rotate with a count to find games where a rook visits all corners
********/

cql( input hhdbvi.pgn )
initial
 T
  4==rotate90 count
       find T  a1