Multi Layer Perceptrons
  - Multi Layer Perceptrons (MLPs) learning with backward
       propagation of error (backprop) are a very popular learning
       algorithm.
 
   - The perceptron is a simple element that takes inputs and converts
       them to a single output.
 
   - A layer of these, with the same inputs, cannot do some tasks.
 
   - If there are multiple layers, with outputs from the first layer
       becoming the inputs to the second layer, you can approximate
       most interesting functions.
 
   - MLPs are universal approximators.
 
   - Using the Backpropagation algorithm, MLPs can be used to learn
       functions from sample input output pairs.