They have many surfaces, some of which normally lie vertically, while others lie horizontally. Because of these surfaces, which act in a similar way to the dihedral angle on bowed kites, this sort of kite does not need a tail. They are normally a strong wind kite. Compound box kites are basically box kites with wings attached to them. They fly in lighter winds than normal box kites and can pull much harder because of the increased surface area being presented to the wind.
Delta wings are the best kites for very light winds.
They tend to be pushed up and forward so that they lie nearly parallel to the wind. Because of this they have a very low angle of attack. Consequently they don't pull very hard at all. The sail forms a billow, and this, combined with a keel in place of a bridle, allows deltas to fly without a tail. The sled is similar to the parafoil in that it relies on the wind to hold it open.