  We analyze loci of triangle centers over variants of two-well known triangle
porisms: the bicentric and confocal families. Specifically, we evoke the
general version of Poncelet's closure theorem whereby individual sides can be
made tangent to separate in-pencil caustics. We show that despite the more
complicated dynamic geometry, the locus of certain triangle centers and
associated points remain conics and/or circles.

Metric Geometry;Graphics;Robotics;Algebraic Geometry;Dynamical Systems