They bounce around on the ground, or a propeller may be attached to them to lift them up into the air for several meters. This is one of my personal favourites. Starmines produce a short but magnificent effect by launching a cloud of stars up into the sky in a single burst. An unconventional but working method of making these has been described here. To make starmines, the art of making stars has to be learned first.
Shells usually constitute the major part of professional fireworks displays.
Shells, again, come in a variety of sizes, types and effects. Many people enjoy making shells as they are one of the most impressive fireworks items and the range of attainable effects is virtually unlimited. In most countries they are only sold to professionals since the amount of pyrotechnic composition is quite large and they require special handling. A simple, small shell of a traditional Italian design is described in the instructions.