dice pencil extender or cap

Pencils are great, however when they are used they get shorter and shorter every time they are sharpened until is is hard to hold them. So an extender makes using them way more fun if they get shorter.

While modifying my [Allen key/hex key extender](https://www.thingiverse.com/thing:2985572) to work as an extender I thought it would be great to add a dice as additional feature to the thing. Since I also have round pencils they are also supported.

The following can be adjusted:

* shape (hexagon or round)
* generate the extender and/or some filler part (makes it easier to print those in different colors)
* use the dice or don’t use it
* the diameter (for a hexagon use the inner diameter)
* the height of the extender/dice
* the minimum thickness of the shell

If you generate a filler you also might want to us it as a cap. If you use the setting cap a little hole is created that might or might not help you to not break the tip of the pencil. If you want to use it as a penc