Deltoids inscribed in a triangle ABC

1) Let t be an angle, M a point on the circumcircle.
2) Take U in BC such that BC and MU form an angle t. Analogously V, W.
3) U, V, W are collinear and the line UVW, varying M, envelopes an inscribed deltoid.
4) Varying t one can obtain all the inscribed deltoids.
Note: The circle inscribed in a deltoid is the circumcircle of the inscribed triangle similar to ABC and determined by the angle complementary of t (figure on the right).