Parametric vacuum-cleaner nozzle

Use this OpenSCAD module to print a new nozzle for your vacuum-cleaner.

## Parameter description

* `d` outer diameter of vacuum-cleaner hose
* `b` width of nozzle
* `l` overall length
* `l1` length of vacuum-cleaner hose
* `l2` length of nozzle
* `strength` material strength
* `round_edges` applies a minkowski sum and scales strength accordingly