board: fix special duplication

board.go

@@ -561,6 +561,10 @@ func readpieces(filename string) (pieces []Piece, err error) {
 						fields[x].placeable = true
 						continue
 					}
+					if rotation != 0 {
+						// only add specials once, do not duplicate for each rotation
+						continue
+					}
 					sm := curPiece.fieldIdToSpecial
 					sm[id] = append(sm[id], FSpecial(c))
 				}