Sand flower
Every year I used to spend New Year with friends in Bideford on the north Devon coast.
And every New Years day we used to go for an invigorating walk along the coastal path to clear the head from the night before.
One year we drew a large octagonal flower using just a piece of driftwood and a ball of string (to make a compass) and the took photos from the cliffs.
It was a race against the tide, and the next day there was no trace of the flower remaining.