OK here are the scans of the 3 possible variations of yellow inverts.
Here's an explanation of how this happens, if anyone is interested. I use the traditional nomenclature of a full printing press sheet, which is later cut into 4 panes with positions identified as UL, UR, LL, LR -- like a 4-paned window. Keep in mind that what we often call "mint sheets" are technically panes that are cut from the full press sheet. In the description below, pane is the equivalent of the commonly used term "mint sheet".
Going from top to bottom, the first stamp shows the basic yellow invert. It occurs in the rightmost 40 stamps of every pane.
-- Circled in red, are the inverted white "4"s in the yellow background. This occurs because the "4" is not filled in with yellow.
-- Marked in a red rectangle, you can see part of the inverted yellow plate number
-- Marked in a green rectangle, is a narrow vertical white strip. This corresponds to vertical white space between stamps, which has been shifted because the yellow is inverted
Middle scan shows the far left position of the leftmost panes. It occurs in the 10 leftmost stamps of the UL and LL panes.
-- note there is no white gutter and no inverted white "4"
Bottom scan shows far left position of the rightmost panes. It occurs in the 10 leftmost stamps of the UR and LR panes.
-- Circled in red is the inverted white "4", but it is almost shifted completely off the stamp
-- Marked in a blue rectangle is a wide white strip. This corresponds to the wide vertical gutter that occurs between the panes (not the stamps)
Therefore, in the original printing press sheet of 200 stamps, the top scanned stamp will appear 160 times, the middle scanned stamp will appear 20 times, and the bottom scanned stamps will appear 20 times. The top stamp will appear on every pane. The middle stamp will only appear on the left-side panes. The bottom stamp will only appear on the right-side panes. You can collect attached horizontal pairs of the top stamp with each of the stamps shown below it, but you cannot collect an attached pair of the bottom 2 stamps.
That's what I learned that year I was bored and plated the all the #1204 panes.