In developmental biology, modeling and simulation play an important role in understanding cellular behavior. We suggest a simple language, the Cell Programming Language (CPL), to write computer programs to describe this behavior. Using these programs, it is possible to simulate and visualize cell behavior. A genome is the program for the development of an organism. The genome, in conjunction with the environment, determines the behavior of each cell of the organism. The program for each cell (written in CPL) plays the role of its genome. The program for an individual cell consists of a set of states. In each state, rules are specified which determine the cell properties (i.e. shape, motility, concentrations of various molecular species, etc.). Different states of the same cell signify different phases in the cell's life. Each cell has a tissue type associated with it. Cells of the same tissue type execute the same CPL program. We use the discrete time simulation model. At every time st...