This picture was created by François Morellet by rotating grids at the angles given in the title. The artist defined a method which was then carried out strictly, without subjective interference. Morellet experimented for a lengthy period using graphite pencil on paper, before he arrived at results which were realised on bigger scale. One observer described the visual effect, when looking at the image for a while, as 'like watching the night sky' in a cloudless night.