Scatchard Sum
This hyperbolic function results from the binding interactions of macromolecules and smaller ligand molecules and is a branch of biochemcal kinetics. When there are two binding sites, adding the linear data as a vectors from the origin results in a hyperbola of interest to chemists experimentally.
This sketch explores the Scatchard plot for two hypothetical binding sites.
Also of interest: The Scatchard plots for two sets of data.
http://tube.geogebra.org/material/show/id/1491063
Michaelis Menten graphs:
http://tube.geogebra.org/material/show/id/1491085