Using a swatch cut from an old T-shirt and a nifty technique called reverse appliqué, a shape is snipped out to reveal a burst of contrasting color behind it.
On the shirt your child will wear, draw a star with the chalk. You can download and trace our 7-inch-star template.
Cut a square from the other tee; it should be large enough to cover the star with 2 inches to spare on all sides. Turn the tee inside out and pin the swatch as shown. Turn the tee right side out again.
Using a running stitch along the chalk lines, sew the swatch onto the shirt front. (We used white thread in the how-to photos for clarity.)
Pinch the center of the star and pull the shirt away from the swatch. Cut a slit, then cut out the star, leaving a 1/4-inch border inside the stitched lines.
Turn the tee inside out, remove the pins, and trim the excess fabric from the swatch, leaving a 1/2-inch border outside the stitched lines.