Updated version with a more smooth gliding corner angle here: https://www.thingiverse.com/thing:3569728
I wanted to guide the filament through the back side of the Ikea LACK stack.
Since I use wood back panels this guide is easy to cut out.
You need two 4mm screws with a max 8mm head to mount the guide in place.
I added the versions for 2 to 5 guide tubes.
Advised is to add a piece of PTFE tube of 5cm. The holes are 4.2mm, the corner will clamp it in place.
Wood back side clips: https://www.thingiverse.com/thing:3488287
Made this as part of my LACK modification for "Original Prusa i3 MK3 ENCLOSURE -Ikea Lack table - Prusa Research" https://www.thingiverse.com/thing:2864118