BYOA
(anesthetic)
gad 
I witnessed this in China back in '90. Used mainly for teeth cleaning.I never saw any actual drilling per se.
It’s a pretty old one, and I’m not quite sure how it’s supposed to work. Though apparently neck-worn portable sundials became all the rage after the invention of the compass.
I suppose you could take it off and put it on the ground. But doesn’t it have to point north or at water or something?
I assumed it needed to be at least held level, and pointed in a particular direction. But apparently this design was held vertically. It’s apparently adjustable for latitude and date.
http://www.mhs.ox.ac.uk/staff/saj/roman/
Interesting.
“Hmm, it doesn’t seem to work.”
“Well get out from under that tree, dumb-ass!”
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