Comment by Groxx

tbh I think zero is a completely reasonable result for a general thought-exercise like this. sleep-based "memory fixes" are quite common in practice, and there's no synchronization at all in the sample.

though there's a lot of fun in here if you allow for optimizing compilers and lack of synchronization. e.g. without explicit synchronization between P/Q and the observing thread (assuming it's the main thread), it's reasonable for a compiler to simply delete P and Q entirely and replace the whole program with `print(0)`