August 2016, Google introduced ads in the local pack. That was one single ad at the top of the local results when you do a search that has local intent. Well, now Google is testing three ads at the top of the local pack but by using a carousel interface to let searchers scroll through the ads without moving the organic listings down too much.
Here is a screen shot of the new test from Joy Hawkins on Twitter:
Here is what the normal ad unit looks like in the local pack:
I guess this is one way of showing more ads in the local pack.
Forum discussion at Twitter.