with a bevel bit and router table.. and the edging strip could be made with 2 passes through a table saw set at about 45 degrees?
Another way to picture what they did was to see it fitting kind of like a v-belt fits in a pulley... you see the back of the belt, but not the sides/edges...
Damn, I have the bug now.. I'd run out and try it, but my neighbors would kill me, since it's 11 pm..lol