So I am attempting to create a simple game where a cat is catching mice. For each mouse that hits the bottom, I want the lives counter to go down by 1, and at 0, cue an end screen. Now when it runs, as soon as one mouse hits the bottom the counter starts counting down infinitely. This is a similar code project to the example in Learning Processing  http://www.learningprocessing.com/examples/chapter-10/example-10-10/

Here is my code:

and the Code for the Mouse object: