When is AB equal to BA?

Explore the circumstances under which a rotation of a shape about a fixed point O followed by a translation of the rotated shape leads to the same result as a translation of a shape followed by a rotation of the translated shape about O. You can make your own shape by dragging the four small red dots. You can fix the size and direction of the translation by dragging the gold dot. You can fix the angle of rotation by using the blue slider. Given a quadrilateral Q, under what circumstances is R[T(Q)] = T[R(Q)] ?