How can random impacts become pressure?

Increase temperature: particles move faster, strike the walls harder, and pressure rises. Each dot only knows its position, velocity, and the collisions immediately around it. Temperature and pressure are not instructions given to the particles; they are summaries of the motion and momentum transfers that emerge from the crowd.

The model checks particle pairs for collisions, so adding particles makes the calculation grow quickly. That cost is part of the lesson: simple microscopic rules can produce familiar bulk behavior, but following every individual interaction is expensive.