After many trials and errors, the four pairs are now forming as expected, the priority mechanism seems to be working also:
When 2 neurons from the input layer are firing, they should be recorded by a single neuron in the first hidden layer, without overlap.
The priority mechanism has to be able to separate patterns correctly, scroll to 0:12 to see what I’m talking about. Basically when a new pattern is started the initial response is not always specific (more than 1 neuron is active in the first hidden layer), but after couple of firing events only the correct neuron is firing.
The mechanism is still fragile but at least I know I’m on the right track… Hopefully next update will be more consistent.