Hand extruder shapes

A few additional shapes for use with this [small extruder](https://www.thingiverse.com/thing:2861701). We use it with Play-Doh and similar modeling compounds.

If you want other shapes, you can copy [this Onshape file](https://cad.onshape.com/documents/f34d6fad8cc1074f98d2d44d/w/77ffbcccd4ebada087b46a67/e/0aa5f45a9174585ace91561f) and tweak the sketches inside.