Posted: Feb 17, 2018 12:26 pm
Aha... The pin in the centre of the curling sheet is used to plug in a distance measurer ("pegs" in bowling) when then end is close.
Lifeboat for the rational mind :D
http://www.rationalskepticism.org/
http://www.rationalskepticism.org/viewtopic.php?p=2615411#p2615411