I swear I thought of this when I was 11:

The photodetectors on the rear surface are used to record the intensity and color of a source of illumination behind the object. The light emitters on the front surface then generate light beams that exactly mimic the same measured intensity, color and trajectory. The result is that an observer looking at the front of the object appears to see straight through it.

What next, mag-lev pavement? (you remember, don’t you Mark?)