A wave-line colour illusion.

Perception 36(9):1396 (2007) PMID 18196705

A new colour-spreading illusion is reported. Illusory colours appear on a white background when three unconnected sinusoidal curves are aligned in parallel when the central line is of a different colour than the other two lines. For some combinations of colours, illusory colours appear not only around the central line but also around the other lines.