Faculty of Health

Deakin Optometry

Lilac chaser

illusion
The illusion was invented by Jeremy Hinton some time before 2005. He stumbled across the configuration while devising stimuli for visual motion experiments. In one version of a program to move a disc around a central point, he mistakenly neglected to erase the preceding disc, which created the appearance of a moving gap. On noticing the moving green-disc afterimage, he adjusted foreground and background colours, number of discs, and timing to optimise the effect.

Instructions:
Stare at the central cross.

You will see a greenish colour disc wherever the pink disc has disappeared.

Eventually, if you stare long enough, the pink discs will also disappear and you'll just see only a moving green disc.

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27th July 2011