This is on the north side of Prospect St. between Bingham and Jones. The hollow letters look nice, and I haven’t seen that style in any other stamps.
Unfortunately, despite it being relatively recent, I have been unable to find anything out about the contractor. Searching for any combination of “tower” and “concrete” or “builder” or “contractor” turns up a whole lot of irrelevant results. I tried searching Michigan’s registry of corporations but there were 22 pages of businesses with names starting with “tower.”
Another detail that incidentally comes forward in this picture is how different the composition of different slabs is. There seems to be a broad range of possible concrete mixes for sidewalks. I know just about nothing about concrete, and I am curious about why there is so much variation.