There is one rule about repeating pattern that separates work that looks right from work that looks almost right, and it is this: you never start the repeat at one end.
The lattice on this apron runs a long way. Begin the layout at the left-hand end and step the pattern across, and whatever fraction of a repeat is left over lands at the right-hand end - a half diamond, or a quarter, sitting on its own against the corner. Nobody consciously notices it and everybody feels it, because the two ends of a symmetrical table no longer match.
So our master Indian artisans set out from the centre instead. The shell is placed first and the centre line marked. The lattice is then stepped outward in both directions at once, and whatever fraction remains appears equally at both ends. The pattern is symmetrical about the middle of the table, which is the only place symmetry is actually read.
Adjusting the repeat by a hair so the remainder lands cleanly - slightly wider diamonds on a longer table, slightly narrower on a shorter one - is the last thing settled before cutting. It is invisible work, and it is the whole difference.