Italian here (Veneto) How do you say it in your dialect? The ball bearing one. I really can't translate it myself into something that could make sense to me.

Also from Piemonte I've never heard the horse brand one but "three hens brand" was used regularly when I was a kid.

My favourite though is "Coma na barca ant el bòsch", like a boat in the woods

Sorry for the necro, but i need to contribute:

In Southern Sardinian, su schiron'e linna in sa domu 'e ferreri(the wooden skewer in the smith's house): something completely out of place.