"We change the rules," Leo grinned. "Enter . Imagine a drunkard’s walk in three dimensions. We can’t say where the glitter will be, but we can describe the distribution of where it might go. We stop looking for a single line and start looking at the 'drift' and the 'diffusion.'"
He turned back to the group, his eyes bright. "Now, let’s go inside and see why dt2d t squared equals zero, but dW2d cap W squared . That’s where the magic starts." An Informal Introduction to Stochastic Calculus...
Leo watched the glitter disappear into the drain. "This math is why we can price an option on Wall Street or predict how a virus spreads through a city. We are learning to calculate the logic of the wind. We aren't just measuring the path; we’re measuring the uncertainty itself." "We change the rules," Leo grinned
One student, Sarah, frowned. "So how do we track it if the math breaks?" We can’t say where the glitter will be,