Still others are poisons if directly ingested or inhaled. The following table lists the principal elements used in modern pyrotechnics. Some elements are used in their elemental form such as particles of titanium, aluminium, iron, zirconium, and magnesium. These elements burn in the presence of air (O2) or oxidants (perchlorate, chlorate). Most elements in pyrotechnics are in the form of salts. A cake is a cluster of individual tubes linked by fuse that fires a series of aerial effects. Tube diameters can range in size from , and a single cake can have over 1,000 shots. The variety of effects within individual cakes is often such that they defy descriptive titles and are instead given cryptic names such as "Bermuda Triangle", "Pyro Glyphics", "Waco Wakeup", and "Poisonous Spider", to name a few. Others are simply quantities of shells fused together in single-shot tubes. A shell containing several large stars that travel a short distance before breaking apart into smaller stars, creating a crisscrossing grid-like effect. Strictly speaking, a crossette star should split into 4 pieces which fly off symmetrically, making a cross. Once limited to silver or gold effects, colored crossettes such as red, green, or white are now very common. A spherical break of colored stars, similar to a peony, but with stars that leave a visible trail of sparks. Essentially the same as a peony shell, but with fewer and larger stars. These stars travel a longer-than-usual distance from the shell break before burning out. For instance, if a peony shell is made with a star size designed for a shell, it is then considered a dahlia. Some dahlia shells are cylindrical rather than spherical to allow for larger stars. A type of Chrysanthemum or Peony, with a center cluster of non-moving stars, normally of a contrasting color or effect. Inserts that propel themselves rapidly away from the shell burst, often resembling fish swimming away. Named for the shape of its break, this shell features heavy long-burning tailed stars that only travel a short distance from the shell burst before free-falling to the ground. Also known as a waterfall shell. Sometimes there is a glittering through the "waterfall". Kamuro is a Japanese word meaning "boys haircut", which is what this shell resembles when fully exploded in the air. It is a dense burst of glittering silver or gold stars which leave a heavy glitter trail and shine bright in the night's sky.