bookmark TumourSimulator Simulates a model for tumour evolution that shows how short-range dispersal and cell turnover can account for rapid cell mixing inside the tumour. TumourSimulator model shows that even a small selective advantage of a single cell within a large tumour allows the descendants of that cell to replace the precursor mass in a clinically relevant time frame. It has also been demonstrated that the same mechanisms can be responsible for the rapid onset of resistance to chemotherapy. This model not only provides insights into spatial and temporal aspects of tumour growth, but also suggests that targeting short-range cellular migratory activity could have marked effects on tumour growth rates. The source code of this model can be downloaded for local use. An interactive version for MS Windows is available and allows the user to set the parameters of the simulation and set up video recording.