GeoTracer gives you one country a day and asks you to draw its border from memory, on a globe with no names and no borders drawn on it. You get a score out of 100 when you submit.
A soft patch of light on the globe shows roughly where to look. The country inside it is unmarked, so you have to know what shape you are looking for and where it sits.
Draw what you remember of its outline, rub out what you got wrong, and submit. The globe then puts the real border next to yours, with the ground you missed and the ground you claimed in error coloured in.
One country a day, the same for everyone, changing at 00:00 UTC. Your result is kept in your browser, so you can come back and look at it later.
You don't have to get the whole border down in one go. Add to it, rub bits out, come back to it. Draw it however you would draw it on paper.
On a touch screen, draw with one finger, turn the globe with two, and pinch to zoom. Undo, Redo and Clear board sit above the tools either way.
The score is out of 100 against the real country. It rewards the shape you enclosed and how closely your line followed the border, so a rough outline in the right place beats a tidy one in the wrong one.
The thing that catches people out is stopping early. If you draw half a border and leave it there, you lose points for the half you skipped, and a careful half can score worse than a scrappy whole. If your score looks lower than the drawing felt, that is usually why.