well i took a simple idea and i think it turned out alrite..... just counted up then down here it goes.
1---1---2---3---4-5-6-789---0---9---876-5-4-3---2---1------9-------------------------1---1---3-4---5-6-7-8---9---0---c---ba---9---8---7-6-5-4---b-------------------------1---1---4-5-6-7-8-9-a---0---a---9-8-7-6-5-4-3-2-1---0--------------------------------