in a suit coat with a non-roped shoulder, the sleeve fabric falls straight down from the shoulder. To make a roped shoulder (it's called con rollino in Italian), the sleeve fabric rises up and out, as if warpping over a thing rope at the top of the sleeve.

It is a great way to add definition and visual substance to the shoulder without making a box, squared-off look. A gentleman with narrow shoulders or a thicker waist may want to consider this option when designing his custom suits.