K'nex Computer reaches 5 bits

My K'nex computer is now more than halfway to completion with 5 fully functioning bits of cpu and memory, as well as 5 keys for keyboard input. I can now add and subtract numbers from 0-31, as well as simply have the machine automatically count up from 0-31 and then start over. At this rate my computer is doubling in power every day and should be completed sometime next week, having achieved 8x the computing power it has at the moment. In order for subtraction to function in binary I am required to add an additional bit, making 9 bits total, though this bit will not be as complicated as the other 8.