Two Butterflies Theorem III
What is it about?
A Mathematical Droodle

This is a further generalization of the Two Butterflies theorem. One was suggested by Nathan Bowler who observed that the two butterflies need not live on the same circle as long as the circles intersect. It appears that the latter restriction is unnecessary. If the circles do not intersect the role of AB - the meeting place of the butterfly contours - is taken up by the radical axis of the circles.

Butterfly Theorem and Variants

1. Butterfly theorem
2. 2N-Wing Butterfly Theorem
3. Better Butterfly Theorem
4. The Lepidoptera of the Circles
5. The Lepidoptera of the Quadrilateral
6. The Lepidoptera of the Quadrilateral II
7. Butterflies in Ellipse
8. Butterflies in Hyperbola
9. Butterflies in Quadrilaterals and Elsewhere
10. Pinning Butterfly on Radical Axes
11. Shearing Butterflies in Quadrilaterals
12. The Plain Butterfly Theorem
13. Two Butterflies Theorem
14. Two Butterflies Theorem II
15. Two Butterflies Theorem III
16. Algebraic proof of the theorem of butterflies in quadrilaterals
17. William Wallace's Proof of the Butterfly Theorem
18. Butterfly theorem, a Projective Proof

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