> To build the dataset, we keep only sketches that have been recognized by the neural network in the QuickDraw game. To prevent imbalance from overly represented countries (e.g., the US), we down-sample the data by focusing on the 100 most prominent countries and capping the number of drawings per category–country pair at 10,000. [p19]
There's a story in Rhodes' book on the atom bomb of Otto Frisch & Liese Mettner discussing the ideation of nuclear fission analogised to cell fission, drawn as a dumbbell viewed head on with the neck of the split a circle inside the bigger cell circle:, where we classically see two cells splitting side by side with a channel between them: she meant exactly the same thing viewed 90° rotated.