The diamond grid on the back of this chair is set out before a single button goes in, because once the first row is pulled the fabric has already decided where the rest will land.
The upholsterer marks the centre line of the back panel first, then works the grid outward from it in both directions. This matters: if the grid starts from an edge, any small error accumulates and the last diamond ends up half a diamond wide against the frame. Starting from the middle pushes the error to both outer edges, where it splits in two and disappears.
Then comes the fullness. A quilted panel needs more fabric than the flat area it covers, because every button pulls material into the hollow behind it. That extra is calculated per row and eased in by hand as each button is tied off, always from the centre outward again. Pull them in the wrong order and the fabric bunches into hard folds at one side instead of falling into even soft ones everywhere.
What you see when it is done is a back that looks like it simply happened. The evenness of those folds is the entire skill, and it is the one thing you cannot rush.