Warm-up: reveal the first letters for free
Available letters
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Bell System Technical Journal · 1951 · C. E. Shannon
A hidden passage of English is typed out one letter at a time. Guess each letter before it's revealed — every attempt tightens the bound on how much information English really carries.
In 1951, Claude Shannon asked a simple question: if you already know English, how much genuine information does each letter of a sentence actually carry? He tested this by having someone guess a hidden passage letter by letter — after seeing everything typed so far, they guessed until they got the next letter right, and Shannon counted how many tries it took.
If English were random, you'd need to search all 27 symbols (26 letters plus space) on average, for an entropy of log₂27 ≈ 4.75 bits per letter. But people usually guess correctly on the first or second try, because English is full of redundancy — spelling patterns, common words, grammar. Shannon used the distribution of guess-counts to compute a lower and upper bound on the true entropy, and estimated English at roughly 0.6 to 1.3 bits per letter: about 75% redundant.
This game reproduces that experiment. Your live "entropy estimate" uses Shannon's exact formula — computed from however many letters you've guessed so far, accumulated across passages so the bound keeps tightening the longer you play. The "warm-up" setting reveals the first few letters of each passage for free before guessing starts, since predicting the very first letter with zero context is unusually hard — those free letters aren't counted toward your stats, only the ones you actually guess.