Stand in front of the elliptical screen and watch your shadows in colours. The shadows are Cyan, Magenta and Yellow.
How do you get them?
Yours body casts shadows in three different places for 3 coloured lights. You get a shadow in Cyan where your body blocks the red light. You get a shadow in Magenta where your body blocks the green light. You get a shadow in yellow where your body blocks the blue light. The rest of the screen is white as all three primary colours mix there.