Sure, you can use a circuit like this to create a one way door, so if you’re building a puzzle box base you can control the players movements through it so they can only go forward and not backward, . You can use the concepts in this circuit in any situation where you’d like to introduce a time delay of a specific length, which is vital for complicated builds like shooting galleries and pinball machines. So, say you had an array of targets, and you need them to stay lit for a limited time while the player shoots at them, you’d use a variation of this circuit to do that. You can also use this circuit any time you need one action to follow another action in sequence. For example, say you’re building an airlock, you want the inner door to open a few seconds after the outer door has closed, you would put a circuit like this between the two doors. Closing the outer door starts the timer, then there is a short delay (you could even add some hissing airlock sound effects during the delay) then the inner door would open. Here are two videos of these examples… https://youtu.be/RpaBZaA47GA https://youtu.be/npzqULt4D6w