The Nelder-Mead method is known as a local optimization algorithm for multivariable functions.
The pictures shown here demonstrate how the Nelder-Mead method works on searching the minimum of a function:
$$f(x,y) = -expleft{-10left[(x+0.5)^2+(y+0.5)^2right]right}$$
$$-1.2expleft{-10left[(x-0.5)^2+(y-0.5)^2right]right}$$
The number on the right bottom corner in the image displays the number of evaluation of the function f(x,y).