If the centers of the 3 and 1 lines are facing out, do a regular Cast a Shadow except the remaining centers at the finish of the movement do a Cloverleaf to fill the vacant space in new 3 and 1 lines by coming in from outside. If the Centers of the 3 and 1 line are facing in, no one does any shadowing--instead, the center four step to a wave, then Lock It and "Extend the Tag" into new 3 and 1 lines with the outsides who do the 3/4 arm turn and spread.