Electron flow. Computer model representing the flow of electrons through a two-dimensional electron gas (2DEG). The gas" is composed of many free electrons, which can move around in only one plane. The 2DEG possesses an electric potential. Irregularities in this potential produce a "bumpy" surface. The model shows the paths taken by three groups of electrons released into the gas from the bottom right corner. The electrons were deflected by the bumps in the gas, producing a branching pattern, with the greatest density of electrons represented by the darkest areas. The fish was added later. Modelled by Professor Eric Heller, Harvard University, USA."