> According to Petronius (c. 27 AD – c. 66 AD) in his work Satyricon, the inventor of flexible glass (vitrum flexile) brought a drinking bowl made of the material before Tiberius Caesar. The bowl was put through a test to break it, but it merely dented, rather than shattering. The inventor repaired the bowl very easily with a small hammer, which he pulled from a pocket in his toga, according to Petronius. After the inventor swore that he was the only man alive who knew the manufacturing technique, Tiberius had the man beheaded. It has been suggested this was either to protect the existing glassmaking industry,[2] to ensure that glass remained breakable as an effective planned obsolescence or because he feared that the glass would devalue gold and silver, since the material might be more valuable.
https://en.wikipedia.org/wiki/Flexible_glass