Sampled-value functions and timing history pitfalls involving $past, $rose, $fell, and $stable.
1. $past Startup History Hole [Medium]
2. $rose Sampled on Clock Edge [Medium]
3. $fell Is an Event, Not a Level [Easy]
4. $stable Repeated Hold Check [Medium]
5. $past After Reset Release [Medium]
6. Vector $rose Sampling Trap [Hard]Work each puzzle before reading the solution: predict the exact output or answer, name the rule that governs it, then check yourself.