A Text Box is a Logic Cube that allows builders to add their own custom text messages to their games.  When a builder right-clicks a Text Box, one of the options is "Settings", which brings up a GUI menu when clicked...  In this menu, a user can type in a message up to 100 characters long, and select one of three sizes to display the message in (small, medium, and large).

A Text Box


The GUI menu for a Text Box


All text sizes, as seen with Logic Cubes hidden