plutus playground simulator wait action question

Question

When using the plutus playground simulator:

1. I'm having trouble finding documentation on the simulator wait actions. What are the differences in functionality between the "wait for" and "wait until" actions?
2. Why did the week 1 auction example require a "wait for" 1 slot action after the close function?

Answer 1

1. "wait for" will wait for x slots until the next transaction is processed. "wait until" will wait until slot x is reached and will then process the next transaction.

2. You need a block that includes the close transaction. Without this extra block the close action is never executed.