I managed to recreate the arc as a printable 3D model - http://shpws.me/3X8r - however I was not able to gain permission to offer my model for sale.
The other day I got back to thinking about the arc and what makes it what it is. Three curved plates form the arc, starting at the bottom from the edge of a triangle to indicating the coners of a triangle at the top back to the bottom again on the edge of another triange displace by one side clockwise (or ccw depending which end you start). Where the plates intersect and overlap, the excess is uniformly removed.
What I've come up with is a wire representation of the edges and creases of the plates and joins. I call it tri-O.
It may be a little difficult to make out the similarities in the geometry, I have trouble seeing it myself even though I created the model.
And this is where you good people come in. How do you think I can better describe Perry's original form? I want to keep the ends closed but am thinking along the lines of the wires representing the plate edges having a square cross-section and maybe the 'crease' wires either as a triangle, or an angled rectangle cross-section.