Perspectrum, made in 1975 by the India-born, Canada-based animator Ishu Patel, is like a gently psychedelic geometry lesson. Colourful squares and rectangles twist, turn and spin to give the illusion of existing in a three-dimensional space, with the visuals accompanied by the staccato plucking of a koto – a traditional 13-stringed Japanese instrument. The result is something resembling vivid, stop-motion origami.