The dog travels some distance to meet a cat friend. The owners were unaware so had nothing to do with the introduction. So how did it come about? Presumably by accident, but the animals seem to be the ones that arranged it all, and continue their friendship together.
The dog can be seem in the pictures calling. It sometimes barks to attract the cat's attention. You can see the cat on the roof, then coming down, and finally going for a walk with it's canine companion. Amazing!