Strolling past a sand dune in Broome, I did a triple take: tracks,  those telling imprints on creatures who have ambled past.  The little double serrations above I am told by Tony, a cheery local, is from a goanna, the circles are Sand Gropers, and the wavy lines, as I had guessed were snakes.  Why is this such a satisfying detail?  Seeing traces of what has gone, like starlight, but here much sandier.