I figured a different way by adding a field in the current agent to save the last state then hide it by giving it a new state of EMPTY -- and then storing that new state (EMPTY) on the (schelling)state location of the agent. It also allows me to simulate death of that agent if another agent moved into that cell. New question: I've got to access the grid created in Schelling after createGrids(). I tried to access it through neighbors but got an empty grid in the new function I created to access the grid. How would I access the grid created by createGrids()? Moses