Mystery piles

We walk past this house most days, and it’s a bit of a mystery. There has been all sorts of building and construction activity going on for months if not years. There have been lots of large vehicles, lots of deliveries of all kinds of building materials, but almost no result to be seen. No walls have risen, no roof is visible. What can they be doing? Are they building underground? Do they keep changing their minds and starting again?
This latest delivery looks like preparation for a giant kids’ play pit. We await developments.