fan duct for CTC Prusa i3 pro B

Edit : requires an update, it's not perfect. don't use it.

It is made to a fan that I have at home.
Diameter 50 mm, ventilator breath on the side.
Ref : B5015L12C de T&T
https://www.dealabs.com/forums/le-bar/le-laboratoire-high-tech--informatique/ctc-prusa-i3/25480?page=36#comment_684838

We can cover the dissipator, or use another 40 mm fan and more.