Among the oldest known production of glass from <a href="https://en.wikipedia.org/wiki/Kosta_Glasbruk" class="extiw" title="en:Kosta Glasbruk">Kosta</a>, <a href="https://en.wikipedia.org/wiki/Sm%C3%A5land" class="extiw" title="en:Småland">Småland</a>, <a href="https://en.wikipedia.org/wiki/Sweden" class="extiw" title="en:Sweden">Sweden</a> is this <a href="https://en.wikipedia.org/wiki/window" class="extiw" title="en:window">window</a> glass from 1742. In the middle is the mark after the glass blowers pipe
<a href="//commons.wikimedia.org/wiki/User:Moeng" title="User:Moeng">Mogens Engelund</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>