>Psychtoolbox>PsychDemos

SadowskiDemo([imgName]);

Demonstrate Sadowski illusion on a specified image file ‘imgName’. if
‘imgName’ is omitted, a default image is used.

The demo will first show the color adaptation image. Please fixate the
fixation cross in the center of the screen. Then press a key. The demo
will show the grayscale only test image. Be amazed! Press any key to
repeat the adaptation phase, press ESCape to quit the demo. If you press
the left cursor key, a white test patch will be show instead of the
luminance image.