: LEAVE R> R> DROP I 1- >R >R ;
: ROLL
DUP NOT IF EXIT THEN
1+ DUP PICK ( n val )
SWAP 2 * (roll) ( val )
SWAP DROP
;
: 2DUP OVER OVER ;
: 2OVER 3 PICK 3 PICK ;
: 2SWAP 3 ROLL 3 ROLL ;