The biological toolbox: a computer program for simulating basic biological and pathological processes.

The program described here has been written to enable pathologists and biologists with almost no computer experience to design complex models of cell interactions. The program although simulating in only two dimensions allows the user to define the individual rules governing cell behaviour using a language called Cell Description Language, then simulates the multiple interactions between the cells to produce a dynamic visual interpretation representing tissue growth and differentiation. The program has been developed using the World Wide Web, thereby giving access to anyone with an Internet connection. The Web technology allows others to use our powerful computers to perform the complex calculations that are necessary and effectively eliminates the problems of modifying and compiling the program to run on more than one hardware platform. The changes that take place during the simulation are presented as a video using the MPEG video format; they may then be viewed on many different types of computers. The toolbox provides a novel approach to computer-based biological simulations and an excellent resource for teaching.