parametric pen holder for collaborative wade

very simple pen holder to use with the carriage. it fits to the longer, not optimized version, but can be adjusted to fit any other.

note that 'centric' version collides with fan shroud .

i've added more sturdy version for holding scrapper , note scrapper needs to be shorter than pen otherwise it will collide with motor.
It is wise to use some screws to bolt the holder not only to carriage but also to air duct of the extruder - it makes it much more sturdy.

TODO:
-redesign fan shroud to fit with that
-design (lightweight) lift mechanism
-design cover mechanism (to prevent pen from drying out)