Guess my RGB

Original Article ↗ Hacker News Discussion ↗

Overall reception

  • Many commenters found the RGB guessing game unexpectedly fun, addictive, and nostalgic (e.g., recalling hand-picking hex codes in early web dev).
  • People shared scores and number of guesses, often getting “Splendid!” in 4–20 tries, with some one-guess perfect matches (sometimes via dev tools).
  • Several described it as a good casual/party-style game and something they’d play with friends or students.

Gameplay & strategies

  • Common human strategy: adjust one channel at a time, watching score changes, effectively hill-climbing in RGB space.
  • Some users treat it as a puzzle: first get a rough hue (e.g., ROYGBIV), then refine by channels.
  • A few compared it to ear-training / equalizer tuning: iteratively “notching out” error.

Scoring function & math exploration

  • The scoring code was posted and analyzed: Euclidean distance in 4-bit RGB, normalized by maximum possible error per target color, then scaled to 0–100%.
  • Several users argued local optima (stuck at 94%) should not exist mathematically; apparent stalls were blamed on rounding or input imprecision.
  • Others explored optimal search strategies:
    • Per-channel hill-climbing, binary / ternary search along each axis.
    • Exploiting the numeric score to triangulate the true color in 3–5 guesses on average.
    • Brute-force strategies using precomputed buckets and variance minimization to choose the best next guess.
  • It remains unclear whether a perfect 3-guess strategy exists; some argue 4 guesses are needed in the worst case.

Bugs & UI issues

  • Reported bug: “New Game” sometimes didn’t change the color and subsequent guesses showed NaN%; this was later claimed fixed.
  • Another issue: some colors (e.g., #952 vs. #951) appeared visually identical while giving non-100% scores; unclear whether due to rendering, perception limits, or a subtle logic issue.
  • Mobile users noted fat-fingering sliders and difficulty moving by exactly one step.

Design ideas & feature requests

  • Requests included:
    • Expert mode with 0–255 channels and alpha.
    • Variants for HSL, OKLab, OKLCH.
    • A forfeit/reveal option.
    • Better tick visibility for sliders.
    • Wordle/GeoGuessr-style social sharing and competitive modes.
    • Camera-based color selection.
  • Several linked similar games/tools and teaching uses (code clubs, recruitment tasks, mobile color puzzles).