We describe a methodology for executing scenario-based requirements of reactive systems, focusing on ``playing-out" the behavior using formal verification techniques for driving the execution. The methodology is implemented in full in our play-engine tool. The approach appears to be useful in many stages in the development of reactive systems, and might also pave the way to systems that are constructed directly from their requirements, without the need for intra-object or intra-component modeling or coding. Short animations demonstrating some capabilities of the play-engine tool are available on the web:http://www.wisdom.weizmann.ac.il/&tilde rami/PlayEngine.
Technical Report