- the relative size of the circles
- meeting at the top at the same time
IN is called when Kite 1 is flying horizontally at ^10, kite 2 at ^25; both at about 60% from centre window. At centre window they both, at the same time, start flying a circle, bottom flyer a large one, top flyer a small one. They meet again at the top, about 10% apart; bottom flyer at ^70. OUT is called when both kites are flying horizontally, about 50% from centre window.