"2D slice of 3D representation of 4-second epoch of EEG from the olfactory
system of the brain of a rat, awake but resting motionless. The trajectory
of a point moving through this space in time traces the subspace that is
occupied by a strange attractor. We have colored it red when the fourth
variable is negative and blue-white when it is positive. The Hausdorff
dimension is 5.92 and we are unable to find geometric order."