In Asia, there are special competitions where kites have complex and are equipped with instruments such as whistles that make musical sounds as the wind blows through them. Although all kites have a similar structure, the variety of shapes is almost endless. The size of the kites also varies greatly - some are so large that several people are needed to control them. Kite-fighting contests are also held, in which competitors use their kites to attack and bring down their opponent's kites or cut their strings.