Saw this over on NeoGaf
They suspect it's covered in stripes to prevent leaks. (different stripe designs for each controller?). Actually looks like all hardware has this weird design.
Controllers for the next Xbox as well as prototype versions of both Microsoft's new, powerful console and the machine's new, mandatory Kinect sensor have been in the hands of game creators since last month. But that's not much of a surprise. What is a surprise is that all of that gear is covered in criss-crossing, radiating black and white stripes. The console codenamed Durango currently looks like a zebra.
About the controller itself:
The controller, according to Kotaku sources, actually seems quite similar to the current Xbox 360 one. Same two analog sticks in the same upper-left/lower-right position, same positioning of the d-pad and face buttons and forward and back buttons. Triggers. Bumpers. Top-center power button. It all seems to be the same, though we can't tell if any of these buttons have been improved--if, say, the d-pad responds more crisply, if the triggers pull more deeply, and so on. The new controller, as we reported more than a year ago, is apparently a little smaller than the existing 360 one. It's still the same basic shape, perhaps with refined contours. It's more or less what people are used to.
The new controller doesn't have any major new input interfaces either, from what we understand. No new buttons and certainly no added screen like the Wii U controller has nor a baked-in touchpad like the PS4's.
http://kotaku.com/the-next-xbox-and-its-controller-are-currently-covered-465487578
