When you click the stop button, it keeps going! Try it! So, how does this work? If you look inside the project, you'll see a script that says "when green flag clicked, forever: reset timer." This means that as long as the green flag is clicked then the timer will always be at zero. If the timer is not at zero after the green flag has been clicked, the stop button has been clicked. Another script starts "when timer is greater than zero," so when the stop button is clicked. I made it change color, but if you use this idea in your own project you can put whatever you want in it.