 The simplex method is remarkably efficient in practice and was a great improvement over earlier methods such as Fourier–Motzkin elimination.However, in 1972, Klee and Minty gave an example, the Klee–Minty cube, showing that the worst-case complexity of simplex method as formulated by Dantzig is exponential time.Since then, for almost every variation on the method, it has been shown that there is a family of linear programs for which it performs badly.