This simulation shows a growing tumor (dark grey) in stromal tissue (light grey). T cells (red) are infiltrating the growing tumor. Note: tumor cell division is accelerated in this simulation for visualization purposes, and occurs much faster than in a realistic setting.
The simulation methodology is explained in this paper: http://journals.plos.org/ploscompbiol/article?id=10.1371%2Fjournal.pcbi.1004280
The source code of our implementation is available here: https://github.com/ingewortel/cpmjs/