IT is surprisingly easy to devise simple line figures which evoke marked illusory contours. Unlike the well known brightness contrast effects, these illusory contours can occur in regions far removed from regions of physical intensity difference; and they can be orientated at any angle to physically present contours. Fig. 1 is the figure described by Kanizsa1. An illusory triangle is observed whose apices are determined by the blank sectors of the three disks. The ``created'' object appears to have sharp contours which bound a large region of enhanced brightness.