Yeah, get some polarised sheeting and some old slides, rip the pictures out of the slides and stick some crumpled up clear cellothane like packaging plastic or even sticky tape in the slide ( hey we are back to blue peter here). Get the polarised sheet and a slow rotating motor ( less than10 RPM) arrange it so the polarised sheet rotates between the light source and the slide you should get the most amazing rainbow like effects, also cracked plastic ( clear obviously) works instead of the sticky tape. Its something to do with the stresses in the plastic and the polarised light.
Simon Cadelic
