MathGuessr

This was posted a few months ago but is too old for new comments:

https://news.ycombinator.com/item?id=43630381

I got a score of 15.6/20 on my second try, which is apparently a "Mathematical Genius". However the difficulty is very uneven because of the randomness of the questions. A few features I might like to see:

1. Adjustable timer. 10 seconds is very fast, it encourages a gut-based answer rather than thinking through the options.

2. A mode that scores based on correctness, not speed. Currently you can get all questions correct but still get a score lower than 20 because of insufficient speed.

3. Better mathematical correctness in graphing. For example, traditionally the natural log function ln(x) diverges at zero is is undefined for x < 0, but this plot shows a symmetric natural log function.

4. Option to zoom in and out of the graph. This is more challenging from a UI perspective but sometimes it's essential for distinguishing functions.

5. Customizable questions sets instead of random questions. I realize this is more complex, but the random questions are often just too easy, e.g. when the graph is obviously sinusoidal and only one of the functions is a sine function, but the main appeal of GeoGuessr is user-submitted maps.