When you’re dealing with a difficult situation or trying to solve a problem—especially one that requires you to think—trying harder or expending more effort can be counterproductive.

When I find myself in that situation, I like to do something that puts my brain in neutral—what Barbara Oakley, author of Learning How to Learn, calls “diffuse mode,” which is when you’re thinking about nothing in particular.

A puzzle game that helps me achieve that—and one which I find enjoyable in its own right—is Water Sort Puzzle. You can find it in the Google Play store here and in the Apple App Store here.

A couple of tips: put your phone in airplane mode to avoid having to watch videos between attempts (or just pay for no ads). If you get stuck, solutions are available on YouTube.