User:WillowW/Todo

Tangent circles

 * Problem of Apollonius
 * Apollonian gasket
 * Steiner chain
 * Pappus chain, arbelos
 * Tangent circles
 * Malfatti circles
 * Seven circles theorem
 * Descartes theorem
 * Coxeter's loxodromic sequence of tangent circles

Inversion

 * Circle inversion
 * Peaucellier linkage
 * Inscribed angle theorem
 * Secant-tangent theorem
 * Power of a point
 * Radical axis
 * Radical center
 * Pole and polar
 * Coaxal circles, pencil
 * Monge's theorem
 * Homothetic center

Rolling circles

 * Cycloid
 * Hypocycloid, astroid, deltoid
 * Epicycloid, cardioid, nephroid
 * Spirograph
 * Hypotrochoid
 * Epitrochoid
 * Deferent and epicycle

Circle packing

 * Circle packing, Circle tesselation
 * Tammes problem, Thomson problem
 * Circle packing theorem

Incircles/excircles of triangles

 * Feuerbach's theorem
 * Equal incircles theorem
 * incircle, excircle
 * Japanese theorem

Intersecting circles

 * Clifford's circle theorems
 * Five circles theorem
 * Six circles theorem
 * Johnson's theorem
 * Lune
 * Miquel's theorem
 * Pivot theorem
 * Poncelet's porism