Optical Delusion

Optical Delusion lesson plan

Design your own optical illusion! Discover a scientific principle called the Moiré Effect. Trick your eyes and brain with lines.

  • 1.

    Fool your brain into thinking you’re seeing an oscillating pattern. By superimposing one grid of lines over another pattern of lines, you can create an optical puzzle. The scientific principle behind this optical manipulation is called the Moiré Effect. Now you can see for yourself how this optical illusion is created.

  • 2.

    On white posterboard, mark two 8-inch long (20.32 cm) strips, one 2 inches (5.08 cm) wide and the other 4 1/2 inches (11.43 cm) wide using a Crayola® Erasable Colored Pencil. Cut out the strips with Crayola Scissors.

  • 3.

    <STRONG>Slotted sleeve</STRONG>: Mark the edges of the wider piece at 2 inches (A) on one long side and 1/2 inch (1.27 cm) (B) on the other. Fold the edges toward each other. The narrower edge folds over the wider edge to make a sleeve.

  • 4.

    Using a straight edge, starting from the (A) edge, draw narrow, even slits. Draw the slits from within one-half inch of the fold to the edge of the paper. Leave an inch of uncut paper on either end of the sleeve. Cut out <STRONG>every other slit</STRONG>, so you have what looks like a stiff grille or fringe. Erase any pencil marks that were not cut away.

  • 5.

    With a Crayola Glue Stick, carefully glue the (B) edge over the (A) edge to hold the fringe in place. The 2-inch strip will slide through this sleeve. Air-dry the sleeve.

  • 6.

    <STRONG>Parallel-line pattern strip:</STRONG> Using Crayola Fine Tip Markers and a straight edge, draw a pattern of parallel lines on the 2-inch strip of paper. For added interest, draw a line down the center of the strip and have the lines radiate out. C

  • 7.

    Carefully insert the decorated strip into the sleeve. Slowly move the design inside it. Watch the patterns appear to move and distort. Flip over the decorated strip to see your second Optical Delusion. Trade strips with your classmates to see more puzzles


  • Students implement precision mathematical accuracy and cutting skills within an artistic context.
  • Students create a tool that enables them to gain a hands-on understanding of the complex scientific principle called the Moiré Effect.


  • Experiment with various colors and combinations of colors. Use different types of lines (straight, wavy, zigzag, diagonal) to see what happens.
  • Visit a contemporary art museum to find artists who use optical tricks in their art. Op Artists are known for their optical experimentation.
  • Research the scientific principles found in other optical illusions such as the Zollner Effect. Match these principles with the examples you find in optical illusion books. Draw your own optical illusions.