As the networks that feature graphs were initialized to zero, we think this reflects some strage joint overfitting that, at round 90, was discovered by all networks and reversed. Readjustments can be seen to occur shortly after round 90 and are reflected in both test and validation sets. The results do not suggest that random initialization is better or worse than initializing to 0. The hidden nodes have bright and dark spots in the region that corresponds to the fingers. Some elements which may have factored in to the ease of the problem includes the background against which we photographed hands.
All right images share the same background as do left images.
In the image above, the most negative and positive spots are in the center of the hand and there are no extremes in the background. Furthermore, if in one picture of the number 3 the hand is a mere finger - width to the right of where it appears in another image, this will have a strong impact on the error.