Step 3Taking the pictures
iImage Information

When we insert a hard plastic item into the field between the laptop and the camera, the birefringent property of the plastic causes the light's angle of polarization to change, since our light is no longer "cross polarized" it becomes visible again to the camera. And since different wavelengths have different refractive indices the visible light appears as a rainbow of colors. Exposures are on the order of 1/2 second so a stand should be used to hold the object.
Have Fun.
When did you realize that plastic in between two polarizing filters would achieve this effect? Learned or experimented? Either way, brilliant. Just brilliant.