a) Design a four bit BCD counter using T flip-flops. The counter will count from 0 to 9, and repeat. In your logic table, if the current state is between 10 and 15 set the next state to 0. This way if the circuit starts in an 'illegal state' it will immediate correct itself.

b) Once you have designed your counter, build it in Logisim, available on the Additional Materials page of this wiki.