This summer I visited here in Holland the most well known prison that we have here. Just as a tourist for an afternoon and not for a stay for a few months
This prison called Veenhuizen was a community where prisoners lived with and worked for the villagers of Veenhuizen. I visited the museum which had an exposition about punishment for criminals from the middleages till the present. Exposed where among many artefacts two execution swords dated around 15-1600. Used here in the Netherlands.
Just a broad flat double edged sword, just like a mediaeval knight sword. The tip was square, nothing special.