The gathered end of a bolster is the smallest piece of work on this couch and the one most likely to look wrong.
A bolster end is a circle of fabric drawn in to a single point at the centre. All the surplus material has to go somewhere, and it goes into pleats radiating from the button. Do it carelessly and the pleats are uneven - some deep, some shallow, some folded one way and some the other - and the end looks gathered rather than pleated.
The way to make it read properly is to fix the number of pleats before starting, and to make it an even number that divides cleanly around the circle. Each pleat is then formed by hand at its measured position, folded in the same direction as every other one, and worked towards the centre so all of them arrive at the button together.
Fold them all one way and the light runs round the end in a single spiral. Mix the directions and you get alternating bright and dark wedges, which on velvet is unmistakable.
The button then goes in dead centre, covered in the same velvet, holding the point where every pleat meets.