Unfortunately the new Attachment max is 1000kb and I have new photographic evidence of a pallet phenomenon, but can't upload... namely, my horses are physically constructing inverted V pallets in their paddock!
I built their round bale hay rings out of pallets; five pallet sections usually encloses a bale. Once they've finished the hay in the ring, one of the horses (Treat, by name) will pull the ring over with his teeth until there is a distinctive inverted V produced... he'll even orientate it structure so that the V is visible to me from my house.
It's as if to say,"OI! We're all out of hay over here!" Hopefully, I'm not anthropomorphising but, could these pallet structures be an attempt at communication!