Brownian Motion
2D random walk with MSD vs time, theory line ⟨r²⟩=4Dt, and slope fit for D.
About this tool
Brownian motion in 2D: ⟨r²⟩ = 4 D t. Set D, horizon T, and particle count; press Run to accumulate trajectories. Green dashed line is the MSD slope fit → estimated D.