Not 100% sure of your intention but one thing that does stand out the unnecessary "every tick" with the sub events - try removing that...
also the first ("line" 2) where you are making sprite and sprite 2 invisible ?
Sorry for the delay.
Not sure whether you still think I am stuck, or wondering how I came to my solution?
Either ways, the "Experiment 3 Copy.capx" is the solution to my problem, albeit in a weird way, so don't worry, it has been solved.