Coasters Made From Beer Bottles' Caps

Another way to display beer bottle's caps
Well, I had lots of caps no use for a second tray, So I decided to make coasters with them.
I used rubber and Petri dishes. When using the upper part you cas put 8 caps on it, the lower part fits only 7 caps.
The difficulty is to cut the rubber layers (cause they'll have to be alligned in the end). In the first try I used contact glue, the others I decided to sew the layers together