A free program for Android, by mAppsTech.

If you are a user of the Android operating system, you can use the Multi Window app to split your screen in two different sections. 

The Multi Window app allows you to create multiple windows within one application, and you can switch between them using a simple tap and swipe. It also supports a variety of different layouts.

You can use the app to split your screen in two, and then you can use the two split screens within one application.

The Multi Window app also allows you to drag and drop icons from one window to another. You can also create an icon on the home screen of your phone or tablet that will allow you to quickly open one of your split screens.