Displays are used to show the contents of your windows on physical hardware such as a computer monitor or a touchscreen display.
Screen API provides the functionality to let you create applications that write to multiple windows and displays simultaneously. Screen supports multiple displays, but it can be quite tricky to create and manage an application that uses multiple displays. You need to consider threading, performance, and graphics optimization. Displays are independent of each other, and each of your windows can be associated with only one display.
You can provide configuration that's meant to be applied to the physical displays supported by your platform in the configuration file, graphics.conf. Refer to Configuring Screen for more information.