This form, a "print" of a leaf on the pavement, is a road's memory of weight.

The process can not be reversed. Even when you recognise the form and imagine the weight, the original leaf and the moment of pressure can not be recreated.

" ...memory ... is like a great field or a spacious palace, a storehouse for countless images of all kinds which are conveyed to it by the senses. In it are stored away all the thoughts by which we enlarge upon or diminish or modify in any way the perceptions at which we arrive through the senses, and it also contains anything else that has been entrusted to it for safekeeping, until such time as these things are swallowed up and buried in forgetfulness. When I use my memory, I ask it to produce whatever it is that I wish to remember. Somethings it produces immediately; some are forthcoming only after a delay, as though they were being brought out from some inner hiding place; others come spilling from the memory, thrusting themselves upon us when what we want is something quite different, as much as to say 'Perhaps we are what you want to remember?' ... Some memories present themselves easily and in the correct order just as I require them. They come and give place in their turn to others that follow upon them, and as their place is taken they return to their place of storage, ready to emerge again when I want them."

St. Augustine: Confessions