At the moment, various actions can be triggered by popping a shape/a group of shapes. These are simply implemented in the level files using only one line for one action, but are a great help for creating more dynamic levels.
This will be extended by the ability to trigger one or more shape spawns on a pop, and maybe a few other things. Hopefully, it'll also be possible to change the trigger type - for example, when players enter or leave an area.
Speed bonuses now randomly offer an imploding shape, which does this: