Image Credit

Description:

A smiley face drawn on a white paper; the white paper rests on an orange larger paper (lower right corner). A set of six pictures of drawings of happy faces. Each circle of a face takes up almost all the space in the picture; all have a small orange strip visible above and below the drawing (upper left corner) .

Source:

Sabine De Brabandere, Science Buddies

License:

Science Buddies