[jacquesm]

You can make a clock easily enough: two NAND gates, two resistors, two capacitors. If you use parasitic components you will get a pretty wild resonance so better to nail it down by using something a bit more stable. But in principle it will work just fine.

Agreed on the 'preemtive multitasking' bit, but that has little to do with this subject. And it is kind of embedded in the name, you need something to do the pre-empting which by definition has to come from outside.

But building a functional computer with just NAND gates is absolutely possible, even if there are better ways, just like you could use Brainfuck or combinators to do meaningful computation. The whole idea of the course is not to give some kind of purist model for computation but to show that the essence of a computer can be boiled down to some very simple building blocks. So the title of the course is misleading only if you want to pick nits. Course titles are made to attract students and to give broad cover to what the course is all about, not to satisfy language purists.