Size estimation
A small test of your sense of proportion. Original geometric edition.
A good eye for proportion?
Five bars, one reference. Estimate each bar’s length as a percentage of the reference. No timer, no real-world measurements.
How to play
Compare the purple bar with the reference directly beneath it. If they are equally long, enter 100%. If the purple bar looks half as long, enter 50%. Play five rounds without a timer. Input accepts 1–300%, with one decimal place.
The data and score
These are abstract shapes with authored ratios, not facts about buildings, animals or other physical objects. Both bars use the same CSS length scale in your browser. The targets are fixed in geometry-1; replay is a practice exercise, not a secret competition.
Each round gives max(0, round(100 × (1 − |guess − target| ÷ target))) points. A perfect estimate earns 100; five perfect estimates earn 500. For example, guessing 90 for a 100 target gives 90 points. The geometric reference is the authored ratio itself. Rendering basis: MDN: CSS width. No real-world pixel-to-centimeter accuracy is claimed.
Rules and data: geometry-1. Locally authored SVG art and code. No external assets or personal data needed.
