Science Centre Singapore is celebrating 40 years of experiential science with a permanent exhibitions exploring the world of optical illusions. This men or pillar optical illusion is a good example of a figure-ground optical illusion. The pillars in this optical illusion are actually the figures, since they are in the foreground, and the men are the background. The projection mapping which appears to the viewer periodically as they blink. Playing around with the notions of size, shape, colour, light and shadow, these ambiguous figures challenge how humans view and interpret negative space or background.