Isoquant

An isoquant map where production output Q3 > Q2 > Q1. Typically inputs X and Y would refer to labor and capital respectively. More of input X, input Y, or both are required to move from isoquant Q1 to Q2, or from Q2 to Q3.
A) Example of an isoquant map with two inputs that are perfect substitutes.
B) Example of an isoquant map with two inputs that are perfect complements.

An isoquant (derived from quantity and the Greek word isos, ίσος, meaning "equal"), also known as iso-product curve or equal product curve in microeconomics, is a contour line drawn through the set of points at which the same quantity of output is produced while changing the quantities of two or more inputs. The x and y axis on an isoquant represent two relevant inputs, which are usually a factor of production such as labour, capital, land, or organisation. Isoquants are level sets of the production function.