see http://redlcv.blogspot.com/2018/ for a short explanation
This code is for educative purpose and was developped under macOS 10.14
Are included 3 files
neuralNN.red: a basic library for backpropagation algorithm
neuraln1_5.red: graphical illustration of running network
neuraln2_2.red: code sample with hidden neurons calculation
This is really illustrative and must be improved!