A firework shell which bursts with a ring pattern, a smiley-face, or a star pattern can be a unique and creative addition to a fireworks display. Suddenly, after a procession of fairly typical full, spherical shell bursts, a simple ring of stars, or a display of four or five of them fired simultaneously, changes the focus of attention of the audience. “Hey, here’s something different,” they’ll think to themselves.
Pattern shells have some distinct advantages and disadvantages to their construction. They don’t use nearly the quantity of firework stars that a fully loaded shell would use, so if I have a few stars of a particular size and color, they might come in useful in a pattern shell. Patterns can be chosen to coincide with a particular theme in a show, with blue stars in a patriotic section, or pink hearts in a romantic interlude.
On the other hand, it will be hit-or-miss when it comes to the pattern’s orientation in the sky when the shell bursts. The smiley-face may display upside-down, or the ring may be seen on edge by a portion of the audience, looking more like a simple line in the sky. For this reason, most display designers choose to fire 4, 5, or 6 of the same or similar patterns at the same time. That will usually result in the audience in a particular location seeing at least 1 or 2 of them in the desired orientation.
If 6 ring-pattern shells of different colors are fired at once, the audience at one end of the field may see, say, the blue and red ones as true rings, and imagine all of them being the same shape.
Ring shells can use simple color stars, which leave no tail behind them, as in the photo above, or tailed stars can be employed, as below.
This Escher print, “Vuurwerk,” is on the cover of Pyrotechnica XI. It shows a pattern I would expect a ring shell of slow-burning, silver-tailed stars to display. It would have to be oriented so that the ring broke “flat” in order to display the “parasol” of stars just right.
A small rising comet tail produces the “handle” to the umbrella.
An advantage to using patterns such as rings, stars, squares or triangles is that they can break in many directions that still have them look correct, as long as they don’t break on-edge to the viewer. A smiley-face has to break in just the right direction to be recognizable.
The star-in-a-ring pattern shown below would look correct if it was rotated any number of degrees clockwise or counter-clockwise. It would also look fine if it was flipped 180 degrees front to back. The only way it would not show up well is if it broke on-edge to the viewer.