Interesting speculation.

Ironic, too, that 500 years after Leonardo wrote this and other
passages , a Neapolitan artist named Raffaele makes his living, or so
he told me, by "drawing" with his scissors the profile outline of
tourists'  heads as they come out of one of Rome's most famous
archaeological sites -- the Roman Forum.  Raffaele charges all of 5
euros for these modern-day line shadow drawings -- and he dashes
them off in about 4 minutes. Judging from mine, which he insisted on
giving me for free, Raffaele is pretty good at executing what
Leonardo described as man's first drawing.

In fact, the accuracy in the eyes and hand of this modern-day, Italian
Raffaele, and, of course, his gift ... left me with a feeling of humility.
That day, I had spent about three hours myself working on a very
detailed pencil study of three columns from the Temple of Vesta in the Forum.

​

f I hadn't met Raffaele that day, I might not have thought at all
about how many 3- or 4-minute drawings I had had to dash off
myself -- in my time -- to arrive at some sense of knowing what it
means to draw the form of a column.  Surely, drawing a living
human figure in motion is at first glance not the same as tracing a
line around the silhouette of a head or figure, cast in shadow against
a wall.  For example, these nude studies came from 20 or 3-minute
poses of a nude female model here in Rome recently, and at first
glance they are nothing like Raffaele's 4-minute, scissor portrait of
me! And yet  they are as reliant on right proportion and coherence as
are the features of a head in silhouette; they must have a uniqueness
and a life force as well. And the artist must be able to grasp this
essence in the same  split second "flash of the scissors" that it takes
my Neapolitan artist to earn his living today outside the Roman
Forum.
Forum.