This paper introduces particle systems as a method for modeling fuzzy objects such as fire, clouds, and water. Particle systems represent an object as a cloud of primitive particles that define its volume. Over time, particles are generated, move, change form, and eventually die. This approach allows for dynamic and fluid changes in shape and appearance, which are not possible with classical surface-based representations. Key advantages include ease of motion blurring, procedural control, and the ability to model complex dynamics. The paper discusses the basic framework of particle systems, their application in the Genesis Demo sequence from the movie *Star Trek II: The Wrath of Khan*, and other applications such as fireworks, line-drawing explosions, and grass. It also outlines ongoing research, particularly in modeling clouds, and highlights the potential for particle systems to address temporal aliasing and improve the realism of computer-generated imagery.This paper introduces particle systems as a method for modeling fuzzy objects such as fire, clouds, and water. Particle systems represent an object as a cloud of primitive particles that define its volume. Over time, particles are generated, move, change form, and eventually die. This approach allows for dynamic and fluid changes in shape and appearance, which are not possible with classical surface-based representations. Key advantages include ease of motion blurring, procedural control, and the ability to model complex dynamics. The paper discusses the basic framework of particle systems, their application in the Genesis Demo sequence from the movie *Star Trek II: The Wrath of Khan*, and other applications such as fireworks, line-drawing explosions, and grass. It also outlines ongoing research, particularly in modeling clouds, and highlights the potential for particle systems to address temporal aliasing and improve the realism of computer-generated imagery.