MOTIVATION:
The use of geometric shapes is common in optical illusion. Working to create an optical illusion will give students experience with positive and negative shape, as well as contrast and pattern.

WHAT YOU NEED:

• Drawing paper
• Rulers, circle templates (plastic lids work well)
• Markers
• Pencils
• Erasers

WHAT TO DO:

1. Demonstrate for the students how to trace the width of the ruler along the paper, creating vertical lines, by lining up the ruler vertically along the short edge of the paper;
2. Draw at least 5 different geometric shapes of different sizes on the paper in an interesting design; (Shapes could include squares, diamonds, stars, rectangles, octagons, triangles, etc.)
3. Using the markers colour the first column, but omit the space inside the geometric shape; (plan ahead of time which sections will be coloured, by placing a light X on the section)
4. In the second column, colour all the inside the spaces of the geometric shape; (the opposite of the first column.)
5. The third column omit the space inside the geometric shape; (opposite of the second column, same as the first)
6. Continue across the paper, one column at a time, alternating coloured with white shapes and white with coloured shapes.
7. When all the columns are finished, colour all the white shapes with a contrasting coloured marker to complete the optical illusion.