A concentrated pulse diffuses into a Gaussian. Its width grows as and its peak falls as ; in two dimensions these changes preserve the total integral over the plane.集中的脉冲扩散为高斯分布：宽度按 增大，峰值按 降低。在二维平面上，两者恰好使整个分布的积分保持不变。
The mesh shows this density spreading with time. The plot is a finite window into an unbounded plane; each animation cycle restarts the same diffusion process.网格显示密度如何随时间摊开。画面只是无限平面的一块有限窗口；每轮动画重新演示同一次扩散过程。