  Given a triangle, a trio of circumellipses can be defined, each centered on
an excenter. Over the family of Poncelet 3-periodics (triangles) in a
concentric ellipse pair (axis-aligned or not), the trio resembles a rotating
propeller, where each "blade" has variable area. Amazingly, their total area is
invariant, even when the ellipse pair is not axis-aligned. We also prove a
closely-related invariant involving the sum of blade-to-excircle area ratios.
