A representation for the three-dimensional structure of proteins that was proposed by the US biochemist Jane Richardson (1941– ) in 1981. In a Richardson diagram an alpha helix is represented by a thick tube or a coiled ribbon and a beta sheet is represented by a thin tube or a line or an arrow. Richardson diagrams were originally drawn by hand but are now generally computer-generated. They have been used very extensively both in technical research articles and in textbooks, as they are very useful for demonstrating the overall three-dimensional structure of a protein.