Projective Morphology 14: Progression and Involution

Sometimes transforming something into itself changes it.

Familiarity with harmonic conjugates and with projection is presupposed.

A method for constructing tangents to a conic with nothing but a straight edge was given in the presentation on poles and polars.

This presentation is part of a series:

Other topics: line segment and point segment, hyperbolic measure, parabolic measure, elliptic measure, growth measure, step measure, circling measure, Euclidean geometry, Steiner circle, Steiner's double-point construction, projective geometry, visualization exercises, Georg von Kaufmann, George Adams, Jakob Steiner