Representing the errors

 While building our neural network, our actual goal is to build the best possible solution, and not to get stuck with a sub-optimal one. We'll need to run a neural network multiple times. 

Consider this error graph as an example:

This is a graph depicting the amount of errors in different solutions. The Global Solution is the best possible solution and is really optimal. A Sub-Optimal Solution is a solution that terminates, gets stuck, and no longer improves, but it isn't really the best solution.