a proof of work is a self-referential digital artifact.

it is information which represents the computing cost to produced itself. this is a subtle but revolutionary concept in computer science because:

all other information IGNORES the computing costs required to produce it. we know these costs exists, but we ignore them. that is, we know that it takes electricity and silicon to produce information, like the words in this tweet that are appearing on your screen. however, we don't think much about it. we treat it as an incidental cost, we don't track its origin & chain of custody, and we strive to minimize it.

proof of work is the opposite. the information being portrayed in a proof of work IS the computing cost required to produce it. we rigorously track its origin and chain of custody, and we increase that cost parabolically. In other words, THE COMPUTING COST REQUIRED TO PRODUCE A PROOF OF WORK IS THE PRIMARY FUNCTION AND VALUE OF PROOF OF WORK.