The message
from Janet Baraclough contains these words:

Yan tan tetherer was a counting system used by shepherds iirc.

Still is, and comes from the Old Norse. [5]

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm

[5] Not an old horse.