This time instead of overlapping (&&) the two cards which created the POGO HAMMER, you use the two codes to double-punch (||) a blank card, producing a different hole pattern.
The result is the HAMMERHEAD POGO RIDE. It doesn't look like it's as much fun as the original ride, but to be fair it's probably a lot safer.
Double-punching cards creates patterns with more holes, rather than less holes by overlapping cards. This strikes you as a viable method for combining more than two items without whittling down to too few holes, or too many! Just mix up the overlaps and double-punches, and the sky's the limit.