IFS fractals are more related to set theory than fractal geometry. Images of fractals can be created by fractal generating programs. Current research of Fractal Expressionism focuses on human response to viewing fractals. Patterns relating to fractals and fractal systems may also be observed in certain variations. Some software programs can create random terrain using fractal algorithms. The Julia set and Mandelbrot sets can be considered as icons of fractal art. Random outcomes are generated using a fractal recursive process. There are two major methods of two dimensional fractal generation. Several formal mathematical definitions of different types of fractal dimension are listed below. Similar algorithms are used in the creation of fractal surfaces. Lichtenberg figures are examples of natural phenomena which exhibit fractal properties. Squares can be used to generate similar fractal curves. Bryce is a 3D modeling, rendering and animation program specializing in fractal landscapes. In colloidal physics, systems composed of particles with various fractal dimensions arise. These parameters are useful for applications of fractal theory such as classification and identification.