The visual ambiguity created by an ellipse is a theme that Eliasson has explored over the years in numerous watercolours and glass works, as well as in architecture and installations. The mechanism is beguilingly simple: an ellipse appears to be a circle viewed in perspective, and a sequence of ellipses conjures the motion of a disc rotating in space. The illusion stimulates a subtle destabilization in the viewer’s perception of space.

For this work, made from hand-blown coloured glass mirrors, two vertical sequences of ellipses overlap. The overlapping sections resemble a complex diagram that is irregular and abstract. The effect produced by overlaid layers of transparent colour is another of Eliasson’s recurring interests; the appearance of transparency in As yet unthought thoughts about moss is simulated by glass panes in a range of different shades.