RHY.5:5.2 - A polygon hides an entrance

A constructed cyclic onset pattern occupies positions 0, 3 and 5 in eight equal units. A shape comparison treats rotations as equivalent. That representation is useful for comparing the relative arrangement.

Now a musician needs to enter at the start marked by another performer. The unmarked shape cannot identify that origin. Add the reference point and direction of traversal, giving the ordered positions relative to them. Keep the rotation-invariant view for the shape question; use the marked one for entry. A single representation need not answer both questions without modification.