https://archive.ics.uci.edu/ml/datasets/Optical+Recognition+of+Handwritten+Digits
https://learn.ml5js.org/docs/#/reference/knn-classifier
https://github.com/ml5js/ml5-examples/tree/release/p5js/KNNClassification/KNNClassification_PoseNet
https://github.com/CodingTrain/website/blob/master/learning/ml5/4.1_save_load_model/P5/sketch.js
https://p5js.org/examples/image-create-image.html
https://p5js.org/reference/#/p5/pixels
https://p5js.org/reference/#/p5.Image