[All Darc]

Tesla's "glass metal" had different results :

First was fine :

https://www.youtube.com/watch?v=V-0UdLOC2iQ

But then : https://youtu.be/6Q3uaepRCl4?t=73

Was the exact same ball???
Or the guy was stronger that day???

Anyway if the window was slightly curved instead od straight, if would resist better.
Test (looks the same kind of ball) with curved "metal glass" :

https://www.youtube.com/watch?v=TWzUh53H_VU