Here is a 7 segment counter circuit based on IC 74LS90 TTL. This can be used in conjunction with several circuits where a counter to show the progress adds a little more attractive. This circuit accepts any TTL compatible logic signal, and can be extended easily. You can add more digits by building a second (or third, or fourth, etc. ) circuit and c
onnecting the pin 11-6 junction of the 74LS90 and 74LS47 to pin 14 of the 74LS90 in the other circuit. You can keep expanding this way to as many digits as you want.