Let's see what happens if we model this equation on a coordinate grid.

来看一下我们在坐标轴上模拟的情况。

Then, we step ahead in time, and the proportions in each group change according to the model's equations: some susceptible people become infected and some infected people become " removed" , by recovering or dying when enough time passes.

随着时间的推移，每一组中的比例根据模型的方程式而变化：一些易感者被感染，一些被感染的人在足够长的时间后通过康复或死亡而被“转归”。