Kinetic Sand
Kinetic sand is a three-dimensional building toy made of 98% sand and 2% polydimethylsiloxane that mimics the physical properties of wet sand. Kinetic sand was originally designed for sculpting but is commonly sold as indoor play sand for children. In appearance it resembles light brown sugar. It can be molded, it sticks to itself but not to most other materials or surfaces, and it does not dry out.