Lorenz

In 1963 Edward Norton Lorenz (23.05.1917 - 16.04.2008) developed a model for atmospheric convection (see https://journals.ametsoc.org/view/journals/atsc/20/2/1520-0469_1963_020_0130_dnf_2_0_co_2.xml and https://www.math.uni-hamburg.de/home/lauterbach/scripts/seminar03/prill.pdf for more details). This model, which was simulated on a tiny digital computer (Royal McBee LPG-30), showed an interesting behaviour which gave rise to research on chaotic attractors.

The system itself is described by three couple differential equations (x' denotes the first derivative of x with respect to time here - more typically it would be written with a dot over the variable name):

x'=σ(y-x)
y'=x(ρ-z)-y
z'=xy-βz