Mystery Tent

A few weeks ago, this structure has turned up in a neighbour's garden. It sits on top of a former sandpit that's been used as a vegetable bed lately (as their children have long outgrown the sandpit age).

It's never been there before, and I am impressed they found a tent that fits perfectly on their old six-sided sandpit. The purpose of this little tent, that's too small for a person to stand in - beats me. Your guess is as good as mine.