Odd occurrences in the Old Herb Garden

Very strange. Woke up this morning and wandered out into the Old Herb Garden for my Daily Dozen exercises. There's a cairn of stones out there that we built one day as part of a "Service of Feeling Generally Well-Disposed to Each Other". Or rather, there was a cairn.
At some point in the night, it would appear that somebody dismantled the cairn, and laid it out in the shape of the Moon Gibbon on the lawn.
What can it mean?