# Tessellation power.

A combined math-art project produces some cool clothes

MATH AND ART combine in Ruth Colton's fourth-grade class at Encinal Elementary School in Atherton, California, when she teaches students about tessellations--identical geometric shapes that interlock in mosaiclike patterns. Artist M. C. Escher was famous for his intricate tessellated designs, but the art can be as simple as a grid of squares.

The young cyclists above are wearing the results of the classroom lesson: T-shirts embellished with their own tessellated designs. The idea is to make a single shape, trace it repeatedly on paper, color it with fabric crayons, then transfer the colored design to a T-shirt by applying heat with an iron.

Each pattern starts with a paper square. The sketch below shows how to cut the squares into shapes that interlock. The process is surprisingly simple!

CREATING THE SHAPE

To make and transfer a pattern, you'll need a 3-inch square of thick paper, scissors, a pencil, transparent tape, typing or newsprint paper, fabric crayons (sold at art supply stores), a white T-shirt that's at least 50 percent synthetic, and an iron.

Draw, then cut out and tape shapes as shown in the illustration below. The cutouts create identical positive and negative shapes. A positive top will always fit with a negative bottom--and one side with another.

To vary the pattern, cut a shape from the bottom of the square and tape it to a side instead of the top, then cut a shape from the top and tape it to the remaining side. The traced pieces will interlock, rotating around a point in groups of four.

ONTO THE SHIRT

Trace several rows of your taped-together pattern piece onto a sheet of paper to create a grid of interlocking forms. With a fabric crayon, outline or color in alternating shapes. For best transfer to the shirt, apply heavy layers of color.

Slip several sheets of newsprint under the T-shirt front and smooth surface. Position your design face down on the shirt. Turn on the iron to the cotton setting, but don't use steam. (To prevent sticking, cover the iron bottom with foil.) Press the iron down, then lift--no sliding--until the image is slightly visible through the paper. Check the transfer by lifting a corner; crayon should show through the paper.

Machine-wash the shirts in warm water on gentle cycle. Do not place them in a clothes dryer; heat could cause color transfer.