One of the most distressing things Noodles did in his first week with us was continual pacing. He paced in circles, making a large circuit which included our basement and garden, always going the same way. If we blocked him or put up obstacles he just changed his route slightly. It was very difficult to snap him out of it using toys or food as he wasn't interested in either initially. This has since changed, of course.
It was as though he was being overwhelmed and wanted to block everything out. We knew he'd be stressed in his new environment but no idea how much. We used a DAP diffuser, which did seem to help and borrowed a K9 Kalmer from a friend. I'm not convinced that it was actually anything other than an expensive set of flashing lights but thought anything was worth a try.
After a few days the pacing gradually subsided and he began to seem more relaxed. However, I've noticed that he reverts to this anytime he's particularly stressed but it's much easier to break the cycle now.
I did think of posting a video to demonstrate this behaviour but it's not particularly pleasant viewing so opted for a cute photo instead.