// convert BD engine elements to corresponding R'n'D engine elements
element = (element == EL_BD_EMPTY ? EL_EMPTY :
+ element == EL_BD_PLAYER ? EL_PLAYER_1 :
element == EL_BD_INBOX ? EL_PLAYER_1 :
element == EL_BD_SAND ? EL_SAND :
element == EL_BD_STEELWALL ? EL_STEELWALL :