Hot -but not burnt- feet

Right now, I have a problem. I'm using the radiator under my desk as an ottoman. The radiator is on, heating my office. As a result, my feet are slightly too hot. That's the problem.

Solution? I need to build some kind of shelf over my radiator. Something just a couple inches higher than the radiator would eliminate the burnt feet problem. Plus, I could put some sort of cushy cover on it without burning down the house, which is an option I don't have for the radiator.