It's mostly glue (but some of it is special glue). Oddly enough, digit recognition was one of the harder parts. iOS11's Vision API has character recognition bu

It's mostly glue (but some of it is special glue). Oddly enough, digit recognition was one of the harder parts. iOS11's Vision API has character recognition but it only gives you a bounding box, it doesn't do the OCR! So for that I ended up ripping up a whole bunch of Sudoku puzzle books from the second hand book store and scanning them in to create a dataset. Then I trained my own nerual network in Keras and converted it to CoreML. The actual ARKit part was really easy, even for me who has never done iOS programming before.