The coin is a 1942 English brass three pence piece with a portrait of King George VI, Elizabeth II's father. The coin is 12 sided, 21 mm across the sides and about 2.5 mm thick. The Latin inscription around the King's head reads:
"GEORGIVS VI D: G: BR: OMN:REX F: D: IND: IMP."
or "George VI, by the grace of god King of all Britain, Defender of the Faith, and Emperor of India". The image on the back is a thrift plant with three flower heads; saving was encouraged at the time. It's not legal tender.

Three_pence.stl is approximately 3 times the size of the original coin.