Can be toggled on or off, with particles wrapping around when off
Prevents the creation of any more particles by interactions when the limit is reached
Clicking can either be disabled, repel particles, or attract particles, and the magnitude can be set by the slider.
Sets the global gravity for the simulation, which applies constant force to all particles. This can be toggled and the magnitude set in the X or Y direction with the sliders.
The background color of a set of interactions determines which particle class is being interacted with. The first box of a color shows the RGB code associated with that particle class. This code identifies the class and how it interacts with other classes.
Each section represents an interaction with another class of particles. The slider determines attraction/repulsion, and the drop-down boxes set the interaction type. OFF just means a collision, CREATE creates a particle of the kind selected from the next drop-down, and DESTROY will destroy the particle that is run into.