A subroutine to represent tridimensional surfaces on a printer.
To get a better idea of the shape of a function, it is often desirable to represent it by a relief map. The representation of tridimensional surfaces is generally obtained with a plotter, tracing the level curves step by step. We are describing here a subrouting allowing the diagrammatic representation of surfaces directly with a line pinter using a blackening whose intensity is proportional to the values of the function.
D003201:Computers; D008433:Mathematics