How to make a block swapper fire twice?

How do I make my block swapper fire once (changing the block) then after a certain amount of timer change back to the original blocks. My block swapper can be seen here:

4

1 Answer

Pulse extender -> dual edge detector.

The easiest would be probably a fader pulse extender, with its output (stabilized by a repeater) observed by an observer (acting as dual edge detector.)

If you need the delay a little longer, add extra comparators in series with the two.