Definition
A ring shell is a pattern shell in which the stars, rather than being spread through the whole sphere, are arranged in a circle on a single plane inside the shell. On bursting they form a bright hoop that widens while staying in its plane, sometimes with a core or central pistil. Because the shell spins in flight, the orientation of the ring at the moment of opening is random: seen face-on it looks round, seen edge-on it shrinks to a line. Makers steady the spin with a tail or careful packing but never guarantee orientation. Ring shells are fired from 100 to 200 mm, in one or several colours, sometimes as concentric rings or a “ring in peony”. It is an elegant figure best fired in volleys so several orientations read at once.
In practice, for the display company
The ring sells on surprise and is best fired in threes or fives to offset the random orientation; the firing plan therefore schedules the volley, not the single shell. PyroDesk treats it as a standard shell for stock and the declaration, and PyroSimulator renders the flat figure with variable orientation, true to what the audience will see.