Lorentz attractor with Polymath + Roassal viz

lorentz.st

sigma := 10.0.
r := 28.0.
b := 8.0/3.0.
dt := 0.005.
system := ExplicitSystem
		block:[:v :t | |dx dy dz x y z|
			x := v at: 1. y := v at: 2. z := v at: 3.
			dx := sigma * (y - x).
			dy := r * x - y - (x * z).
			dz := (-1 * b * z + (x * y)).
			{dx. dy. dz}.
			].
stepper := RungeKuttaStepper onSystem: system.
solver := (ExplicitSolver new) stepper: stepper; system: system; dt: dt.
state := #(10.0 10.0 10.0).

values := (0.0 to: 100.0 by: dt) collect:[:t |
	state := stepper doStep: state time:t stepSize: dt].

b := RTGrapher new.
ds := RTData new.
ds dotShape ellipse size: 1; color: (Color blue).
ds points: values.
ds x: [:v | v at: 1]; y: [:v| v at: 2].
b add: ds.
b build.
b