What Is This?

Day 39

Sorry if you were expecting a post yesterday.  I'm posting when things are interesting and since things have been plenty interesting you might have thought that this was turning into a daily post.  Sorry, not so.  Yesterday's pictures look almost exactly like the day before.  Boring.  Today I have what I would call a mystery picture.

It's a mystery because I have no idea what they're doing.  I imagine it's some sort of waterproofing along with drainage so that water doesn't collect and sit next to the foundation which would probably eat out the concrete.  But this is how it is going to stand over the weekend.