Pure Data, a.k.a. Pd, is a visual programming language and environment for audio and visuals. It is open source and it was made by Miller Puckette during the 1990s. Visual programming means that instead of writing code (a series of keywords and symbols that have a specific meaning in a programming language), you use a graphical interface to create programs, where in most cases, a “box” represents a certain function, and you connect these “boxes” with lines, which represent patch cords on analog audio devices. This kind of programming is also called because of the way the parts of a program are connected, which indicates how its data flows from one part of the program to another.