In a pan, thoroughly mix cornstarch, baking soda, and cold water until there are no clumps.

Cook the mixture over medium heat for approximately 4 minutes, stirring constantly to prevent sticking.

Continue stirring until the mixture achieves a consistency similar to mashed potatoes; it should be thick and smooth.

Remove the pan from the heat immediately.

Cover the dough with a damp cloth to prevent it from drying out, and let it cool for about 1 hour.

Once cooled, knead the dough on wax paper to create a smooth and pliable texture.

Use a rolling pin to roll the dough to your desired thickness.

Cut the dough into your desired shapes using cookie cutters or a knife.

Allow the cut shapes to dry completely overnight to harden.

Once dry, paint the shapes with acrylic paints or markers.

Seal the painted shapes with a coat of Elmer's glue to protect the paint and add a glossy finish.

Attach a pin backing to the shape using glue, or poke a hole in the shape before drying to create a necklace pendant.