A student asked me how is a clock's rising or falling detected? I had never worried about this. I told him his question was beyond the purview of the class but would research. He hates rote memorization. I explained that in beginning ckts, they do not teach you how to make a resistor, capacitor, or inductor, only how to use them. But I too feel his question.I my school books. The sections about counters were quite thorough. So the problem is more lazy students, I think. Since this is a popular assignment. I would say no complete schematics. A block digram may be OK. As it may give a push in the correct direction. But nothing more. We can not take all the fun from the students.