Black Box

A black box is an object that accepts input and generates output without the solvers knowing the rules that govern the operation of the black box. Often, the puzzle involves figuring out how the black box works, then using the rules of the black box to create inputs or outputs with a desired property.

Background[edit | edit source]

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Puzzle Application[edit | edit source]


Black boxes can be designed for any plausible function; in puzzles, however, they most often act upon a text input. Black box puzzles will often also provide some of their "rules of operation" while keeping the functions themselves secret: some will directly have instructions on what constitutes a valid query, while others will reflect part of their inner workings upon being presented with an input.

Black box puzzles are also almost always interactive puzzles.

There will also almost always be a "goal": determining what a certain input will output (while the black box forbids that input from being used directly) or determining what inputs will generate a certain output. These goals are often tied to extraction.

Strategy[edit | edit source]

The key to deciphering black boxes is to carefully craft inputs that allow for discerning the rules. What counts as such an input will obviously vary between puzzles; however, consistency in function is generally valued. If the solver can guarantee that a series of input-output relationships follow the same function, that function becomes easier to identify.

Notable Examples[edit | edit source]

  • Pipe (MITMH 2015) (web) - Click to revealThe inputs are strings, but the outputs are the error messages that occur when the string fails. The only input that makes it through without sending an error back also doesn't return its output, which must be determined to reach the answer.
  • Functional Analysis (Teammate 2020) (web) - Where Click to revealthe input and output are both integers. The output also shows that the black box applies functions based on each digit in the input to the input. The first part of the puzzle is to find the one number that resolves to a 48-digit number; the second part uses the rules as transformations to go between two arbitrary integers.
  • Nutraumatic (MITMH 2021) (web) - A black box puzzle taking the guise of the popular Wheel of Fortuning tool Nutrimatic. Click to revealMuch like Nutrimatic, Nutraumatic uses lowercase letters as literal text and uppercase letters for specific types of wildcards. Unlike Nutrimatic, every uppercase letter has a function, and it only accepts queries that are also words in the SOWPODS dictionary (not to mention that it doesn't recognize non-letters). The challenge is to find a phrase that satisfies a long non-word input.
  • Sorcery for Dummies (MITMH 2022) (web) - Where Click to revealthe inputs are sequences of words and the outputs are strings. The final word is fodder that every previous word acts upon using a function described by its first letter. The puzzle asks solvers to find inputs that resolve to the names of eight types of common fantasy antagonists.

See Also[edit | edit source]