five ways to see the same flow
the plates are five views of one set of nine numbers. none of them contain anything the others do not. they exist because the same deviation is obvious in one view and invisible in another, and which view catches it depends on what produced it.
a flat fill across all nine digits is the signature of sizes chosen by a machine that was not thinking about size. on the first plate it looks like nine bars of nearly equal height inside outlines that are not. on the residual it looks like a strong negative bar on 1 and positive bars on 6 through 9.
a spike on a single digit is one address reusing one size. it barely shows on the first plate and it is unmistakable on the fourth, where a reused size draws a hard horizontal stripe across the scatter of the log fraction.
a lean toward 1 and 5 is a person typing round numbers, which is not manufactured volume and will still cost more. the hook cannot tell the difference between a round number and a fabricated one, because in digits they look the same.
the second digit grid is the one that catches effort. building flow that satisfies the law on the first digit is easy, and doing it on the first and second at once is considerably harder, so a pool that passes the first plate and fails the grid is a pool where somebody tried.