The holy book is generally agreed to be the Kama Sutra, although a Lego or IKEA assembly manual will do in a pinch, with some interpretation left to the user.
The hat geometry is of no consequence, and constantly changes, so long as the requisite hat can be easily constructed from the cardboard that encases a 12-pack of beer. Cans and/or bottles. The average Hubski user typically has easy access to both, in the event of an emergency.
Tin foil is considered “loud”, but decorative, in either case.
Thank you for asking.