This is the 'Confuse-O-Scope', a device which allows you to enjoy having mis-aligned RGB in real life! Guaranteed to cause confusion and irritation with anyone that's worked in TV, printing or theatre lighting.
It uses 3 dichroic beam splitters (search ebay for 'defective cube', you can get big packs for cheap).
Light of any colour is capable of getting through, but the red, blue and green wavelengths all travel via different paths, and the views will look subtly different.
You can also flex the frame a bit and change the RGB alignment, making it overlap or separate.
More info here: