Elegant Geometry Proof
This is a very cool and elegant visual proof.
Given: Triangle ABC with equilateral triangles drawn on each side.
Prove: The segments connecting each vertex of Triangle ABC to the vertex that's not A, B, or C of the equilateral triangle on its opposite side are all congruent.
Drag around points A, B and/or C, to see that the segments always seem to be congruent.
To see the proof, slide the rotation slider from 0 to 60.