zeros cons 0 n__zeros U11 tt L U12 tt activate L U12 tt L s length activate L U21 tt IL M N U22 tt activate IL activate M activate N U22 tt IL M N U23 tt activate IL activate M activate N U23 tt IL M N cons activate N n__take activate M activate IL length nil 0 length cons N L U11 tt activate L take 0 IL nil take s M cons N IL U21 tt activate IL M N zeros n__zeros take X1 X2 n__take X1 X2 activate n__zeros zeros activate n__take X1 X2 take X1 X2 activate X X zeros 0 cons 2 0 0 n__zeros 0 U11 2 tt 0 U12 2 activate 1 s 1 length 1 U21 4 U22 4 U23 4 n__take 2 nil 0 take 2 FULL ./TRS/TRCSR/OvConsOS_nosorts-noand_Z.trs