Although that's a decent UI and gamification with the circles and all, if I seriously wanted to memorize this information, I would just want the data as an Anki deck.<p>Front of card: country name, plus possibly: recognizably large segment of world map containing that country, without highlighting.<p>Back of card: same graphic, with that country colored.<p>Determining whether you got it right is self-evaluation in Anki; if you thought of the correct map shown in by the back of the card, you hit the good button, otherwise bad.<p>This clever paradigm in Anki means that deck authors don't have to develop UI for the user to specify correct answers.<p>Say you want to go from dog breed names like "Yorkshire terrier" to photographs (rather than photo to name). How would you develop a UI by which the machine could test you and confirm that you know? Probably multiple choice is all we have. Multiple choice with too few choices gives the answer away to some extent. Too many choices will overwhelm your mobile device screen. You could ask the use to draw the animal. That would be time consuming and require talent not directly related to memorizing dogs.<p>With self evaluation, you don't need it. You just imagine a Yorkshire terrier as best as you can. Then if you think the back of the card is close to what you were thinking off, you hit Good. If you imagined a Westie, or German Shepherd, so that you are surprised and dismayed by the unexpected Yorkie image, then you hit Bad.