Four quadrants, each starting with a different pure strategy. Watch how they compete at boundaries.
Ethnocentric quadrant (red) typically expands into all others, altruists (green) get exploited,
cosmopolitans (orange) fail to cooperate with each other, and egoists (blue) starve from lack of cooperation.
Altruists (Top-Left)
Cooperate with everyone. Highly vulnerable to exploitation.
Ethnocentrics (Top-Right)
Cooperate with same color only. Form strong clusters.
Cosmopolitans (Bottom-Left)
Cooperate with different colors only. Cannot cluster effectively.
Egoists (Bottom-Right)
Never cooperate. Fail to reproduce without cooperation benefits.