Many pasta shapes developed organically over the centuries as cooks modified preexisting designs to fit new needs. But that's not the approach that Dan Pashman took. He decided to start from scratch after studying the best qualities of pasta. The result of his research is cascatelli.
Cascatelli is, appropriate for its shape, the Italian word for waterfall. Core77 describes how this design simultaneously fulfills several pasta objectives.
The ruffled half-tube on one surface creates a lot of surface area for sauce to adhere to. The elongated edge allows the user to easily stab it with a fork. The right angles on the underside create maximum resistance to teeth, establishing what Pashman calls the ideal "toothsinkability." And the overall variations in textures and thicknesses provide a high contrast in textures.
What I haven't been able to learn from Pashman is the ideal sauce for cascatelli. What would you use?