As far as the viewing audience is concerned, it can look exactly as follows. You borrow a coin and have it signed. A borrowed empty glass is then placed mouth down onto a borrowed beer mat as shown in the demo video on this page. Then, Hey Presto, they witness their coin being banged against the glass where it seemingly visibly penetrates through the glass under impossible conditions.
Two handlings for using a signed borrowed coin are explained, along with another that does not involve the coin being signed but is just as visibly miraculous to all who witness it at close quarters.
Yes, this can be performed surrounded and, done correctly, there are absolutely no angle problems. It is also true to say that there is very little in the way of sleight of hand required. Indeed, in truth, there is a handling explained where no sleights are required whatsoever.
It's also true that there is a way to perform this which hardly takes any real skill or practice whatsoever and yet still looks to those who witness it like some kind of television special effect. They will swear blind that they just witnessed their coin impossibly smashed through the bottom of a solid glass.
An ingenuous gimmick devised by the late Jack Griggs is required. Within this multi-media download package of videos, photos and PDF you will be taught exactly how to make your own custom-made gimmicks, which are bespoke and "invisible" for ideal use in your geographic location and with coins of various sizes.
Don't let the ridiculously low price of this download package deter you from getting what is as shown in the demo video -- a truly reputation-making close-up miracle.