On iPhone, where screen real estate is at a premium, Realmac succeeded in creating a whole genre of innovative and chromeless interfaces, and sold over 600,000 copies of Clear for iPhone.

The Clear app simplifies list-keeping, using a heat map to show the priority of items on your list and a simple swipe functionality to check them off. It's also a lot more visually appealing than ...

13—and you may want to have your game plan ready for the vaccination ... And downloading the CLEAR app is the quickest way to get inside. “It’s extremely easy to use,” he said.