Similar to クラメル・カスティヨンの問題

Incenter–excenter lemma

Japanese theorem for cyclic polygons

Harcourt's theorem

Lune of Hippocrates

Van Schooten's theorem

Fuhrmann circle

Feuerbach's theorem

Pompeiu's theorem

Musselman's theorem

Miquel's theorem

Lexell's theorem

Lester's theorem

Six circles theorem