So, photons exert a tiny force when they reflect off of something. I was thinking about the EMDrive yesterday, and how it supposedly uses radiation pressure for thrust. Then I had this ridiculously funny and impractical idea of how the EMDrive is supposed to work, according to the physics we know. It would best be explained by a picture:
It would use mirrors as fuel, and would leave a stream of mirrors in it's wake as it slowly gets pushed along. It's completely impractical, but would work. I thought it was a funny idea...