I think shot glasses are optimized to be put into various configurations, such as matrices and triangular matrices: http://www.likecool.com/Home/Accessories/Bil

I think shot glasses are optimized to be put into various configurations, such as matrices and triangular matrices: http://www.likecool.com/Home/Accessories/Billiards%20Shot%20Glass%20Set/Billiards-Shot-Glass-Set.jpg http://www.likecool.com/Home/Accessories/Billiards%20Shot%20...