First, I lost track of where this thread went. The Search feature on this forum is cool. I just searched for "trap door" with member number 3 and easily found it.
I finally found the time to work through the routine, and it's a true gem. Very Paul Harris-ish. I like the patter and for that reason would not think of switching into Card Warp. What in the world must Jim have been thinking about to come up with this, and THEN (or was it the other way around) to come up with patter that is such a lovely fit?
Minor comment: At the point where it reads "(That is, reverse it on a vertical axis; the folded edges are still at the top.)," for me, the folded edges were still at the bottom, which made sense.