Four-Color Outer Median Cellular Automata in 1D

Outer median cellular automata (CA) are a functional form of the CellularAutomaton function in Mathematica. The color of the active cell on the next step is determined by first taking the median of the neighbors of the active cell up to a certain radius and then taking the floor of the median. Radius 1 means one neighbor on each side of the active cell, radius 2 means two neighbors on each side of the active cell, and so on up until radius 10). The pairs {active cell color, floor of median of neighbors} are then mapped to rules in color spaces as usual. Here there are four colors. A 1000-member rule space is sampled, since the entire rule space is too large. The CA evolution is 150 members wide and 150 steps long.