“In general, the bigger the shell, the longer it will take to burst and the higher it will go. By inserting the size, firing time, and type of each shell into a firing script, a choreographer can lay out a series of effects that unfold at different heights in time to the music. If he’s using a fireworks choreography software package, he doesn’t have to look up (or memorize) all of the height and timing information for each shell. Instead, he can drag items from a digital catalog directly into an online script.”