Here Loes , in the canteen of my former office, dog of a colleague with a very timely brain for when food could be acquired by her. When the top concrete layering was made a few years before an unknown cat was get inside and walked through the wet cement. It was such a nice effect that we left it that way. Now I think that it was not a complete surprise to someone but of course well for the cat.
Still it was a very animal friendly office.