The PDX is the meat and potatoes of what I do, the original design was called a Quagg, for Quad+Egg, which went through a few alterations eventually ending in the PDX.  The design came from the fish craze on 2001ish  I was riding a few classic Fish in the 5'4"-5'6" range but wanted something longer being 6'3"  As the fish grew in length they started to track, so i combined a fish with a round pin to put some curve in the rail and loosen them up.  Since then of the nearly 8000 boards I've hand shapes the PDX has been by far the most popular,  They paddle great, fast and super loose. Sort of a best of both worlds.