An image of "Optical Illusion with Portraits of Charles II and His Daughter Christine of Lorraine", created by Lodovico Buti in 1593 (Oil on prismatic panels, glass, 82 x 112 cm).

Watch this classical example of the perception of contrasts.

Is this a spiral or a clever composition of circular segments intensified with triangles?

A great resource to discover fun new activities to use in your classroom. Activities are age-appropriate, and span several science topics.

This unknown chalk pastel artist creates unbelievable 3-dimensional images on the sidewalks of the city.

Are the two red segments always the same size? Press the guide button to find out.

Do you see four concentric red squares? Use the green square to find out.

How many triangles do you see?

Observe the red and the green segment and predict if they are aligned.