Batch-printable Face Shield

This design is influenced by the many Face Shield designs floating around. Specifically, I'd like to recognize the excellent designs from
[3DVerkstan](https://www.youmagine.com/designs/protective-visor-by-3dverkstan)
[Stratasys](https://go.stratasys.com/lp-face-shield.html?utm_source=pr&utm_medium=email&utm_campaign=mfg-amer-march-2020&utm_content=covid19)
[Prusa Research](https://www.prusaprinters.org/prints/25857-prusa-protective-face-shield-rc2)

I was dissatisfied with these designs due to their BOM (most require elastic bands), the fitment of the clear shield (most are not secure), but mainly with the *lack of batch-printability*. All of the designs I've seen are not stackable, which means someone needs to babysit the machine and remove parts every few hours.

This design is first and foremost batchable:
If your printer has a support nozzle, add a single layer between parts, and stack them as high as you like. If not, just skip a layer (requires separation with a knife), o