Configurable 40mm fan duct / mount for Wade's extruder

This is a complete redesign of thing #154834 by WeSo (Juan Diego), an adjustable 40mm fan duct / mount for Wade's extruder (but can also be used with any Bowden or direct drive extruder). I kept all the parts compatible/exchangeable with the previous (already good) design. All the parts have been slightly improved (nut traps, reinforcements, better fit and less useless material) and the fan duct itself is a more rounded design with slightly better airflow, but most importantly I wrote from scratch the OpenSCAD source code for all the parts and licensed the code under GPLV3, so it can be edited/modified to taste. The (optional) nice fan guard in the pictures is thing #516392. The eighth picture shows the result of my first ever attempt, without any specific calibration, at printing the infamous bridge torture test (thing #12925) by triffid_hunter. The nineth picture shows the original fan assembly interfering with the X-axis idler, this is solved by adding a pivot joint which also allows more flexible orientation and positioning of the fan duct (see the last two pictures). As of 25-04-2015, you can choose from 5 different layer fan ducts and one E3D cooler fan duct: 1 - The original fan duct by WeSo. 2 - My rounder V1 design with improved airflow. 3 - My V2 version, more curved and with a narrower beak than V1. 4 - My V3 version, easier to print with 1.2mm thick walls, and slightly shorter than V2. 5 - Spinorkit's awesome E3D V6 compatible layer fan duct. 6 - An E3D cooler fan duct. Updates: 13/05/2015: added four new connecting arm variations. 25/04/2015: a new V3 40mm fan duct optimized for compact setups, and a Z-shaped arm. 23/12/2014: please check the awesome remix by Diegomanitas, which allows using just about any fan for the fan ducts. Remember that the larger the fan, the more airflow and the less noise, so always try to use the largest fan you can fit around the extruder. 30/11/2014: added an E3D cooler fan duct for a 40mm fan. Note that this has a different purpose compared to a layer fan duct, it is designed to cool the E3D aluminum body itself. Also note that the 40mm fan for this fan duct should be connected directly to the 12V power supply, and NOT to the RAMPS fan output. 17/11/2014: added yet another fan duct, V2, a shorter, more curved version of V1 with a narrower beak to better focus the air flow. 16/11/2014: I remixed the awesome E3D V6 layer fan duct designed by spinorkit (thing # 217253) and made it compatible with my mount. 14/11/2014: added a pivot joint and an L-shaped arm, to solve an interference between the fan and the X-axis idler. 13/11/2014: added two slightly longer arms, just to show how easy it is to edit the code and create new parts. New! A YouTube video: https://www.youtube.com/watch?v=-Wi_hV2lTlI