Duplicator D9 fan duct

Here's the result of uncountable iterations of trying to improve the part-cooling fan that comes with the Wanhao Duplicator D9 (MKII 400). It's supposed to fit the original 4010 fan without the need of disassembling anything. Just use 2x M2,5x15ish screws + nuts (optional) to attach it.

First I asked myself why wanhao didn't put more effort in their part-cooling design. Now I understand... the original duct-less design is good enough for almost everything. If you still want to try a fan-duct, you can choose from 3 versions (with names that reflect their appearence):

* the poo: This one comes in a rather organic shape (to use an euphemism) and was designed in blender, which I'd like to use as an excuse. The first examples looked quite nice but in attempting to improve the airflow I had to change it over and over again... eventually looking like a piece of crap. However it actually works. Not much better than without a duct though.

One problem with these 4010 fans is their uneve