This triangular-shaped kite is named for and resembles the fourth letter of the Greek alphabet. Invented by NASA, a delta kite can flex and adjust to changes in the wind. The keel holds the spine straight and rigid. The ability to automatically adjust to changes in wind force and direction makes a delta a good beginner’s kite as well as a favorite of experienced fliers. Tails are often added at the center, at the wing tips, or both.