Our 'secret' artist

Along the beach front, and occasionally in the centre of the village, on fairly low level walls......we see small pieces of 'art'....usually plaster caste and everyday articles...
.....such as a bag, a satchel, a purse or a flip flop.
Today I found this very new, and very white, plaster caste 'trainer' shoe on a small wall, on the beach front.
It's a mystery!.....I have no idea who is giving us these gifts.....
They are very life-like......
this one says 'this is not a shoe'....Esto no es un zapato