Petr, there is concrete beneath the caps and tile of the rings, and also under the fountain. We coordinated with the concrete guy.
Tiling the arches is a drawn-out process. Every piece is mechanically anchored, in this case L shaped tabs in each grout joint. This stuff was too thin to drill pockets into. The pieces of the fountain are drilled, pinned, and epoxied. Doing this stuff is very different than doing tile. It's an interesting and fun change of pace from doing tile.
Isaac, I'm only seeing single pictures. Tapatalk is a very strange app. It's a good thing I'm already signed up for the JB tile forum, because otherwise it doesn't exist according to Tapatalk. And you have to pay for the app. So all this stupid glitch stuff is like insult to injury. But what else can we do?