Desktop Program for PC and Mac

The purpose of this software is to display subliminal written messages on the users computer screen on a frequent basis. Subliminal simply means "below concious threshold", and the way we are going to do that is by flashing the message so quickly, and slightly transparently, that the users concious mind can not detect them (yet the sub concious mind can). Of course it will be the user that determines what messages will be displayed. It can be done in any programming language you like. I require a PC version and a MAC version, with an install package for each. Please see attached file for detailed spec and wireframe.