Think is an application by Freeverse that helps you to concentrate on a single application.
On the surface, it works like some of the apps I’ve reviewed here before, particularly Backdrop and Isolator, where it darkens the screen behind the frontmost application.
When you pick an app from the task switcher, it brings that app to the front. But when you try to click onto another application, it brings your app back to the front. You can still use the dock and cmd-tab switcher to switch between applications, though. It acts as a small but effective way of routing you through specific ways of switching applications. I actually wish it was more strict in keeping you on task. I think it would work more smoothly if you had to go through Think to switch to anything else.
It’s free download. Give it a try!