When the precogs predict a murder, the machine in PreCrime carves the names of the murderer on a red wooden ball and the victim on another red wooden ball. What is the point of this? I see a lot of downsides:

  • The process takes a while, which given that reported murders are imminent and every second counts, seems like a problem
  • You can't store them very easily for record keeping
  • The balls are identical except the names, so if you drop them, you could mix up the two and arrest the victim

Given all this, why does the PreCrime machine report its murders through carving names on wooden balls, instead of just displaying them on a screen or printing out a sheet of paper? I know that someone says a screen could be faked, but I find that to be a dumb explanation given that an engraving machine is basically a glorified printer (so why not use that and just have special watermarked paper or something)?

1 Answer 1


Because its a poorly thought out aspect of a beta project intended to impress politicians into expanding Pre-Crime nationwide. Murder is seen as an epidemic around the country, and this program is seen as the cure for it. The wooden balls are a decorative touch intended to be decorative and impress, not be completely practical.

But I believe they also justified it as each ball being unique, and unable to be duplicated or counterfeited. The wood provides a unique fingerprint for each report. From a draft script:

As Jad, Fletcher and Knott show Witwer one of the wooden "eggs". All of them now chewing gum, friendly with Witwer.
FLETCHER: The information we need is embedded in the grain of wood. And since each piece is unique, the shape and grain is impossible to duplicate.

  • 4
    Sound quite reasonable.
    – Ankit Sharma
    Dec 26, 2016 at 6:16
  • 1
    Is there any evidence of a database or something that they use to verify that the unique shape as grain is a valid one and not a counterfeit? It seems like the weak link there is that the database can be hacked to consider a counterfeit one as legitimate (or even a legitimate one as conterfeit in order to cast doubt on an upcoming murder). Dec 26, 2016 at 15:32
  • 1
    The database would likely only contain a one-way hash of the ball's ID, just like today databases usually only contain a one-way hash of the password. You could not determine the ball's grain just form the hash. Dec 26, 2016 at 15:46
  • Are you sure it is the project and not the script that is poorly thought-out? The premise of the movie is that the pre-cogs see the future as it will occur if the police take no action, but the plot of the movie is that the pre-cogs sees the future contingent entire on police action. The dialog again and again affirms that the system is perfect, but the plot demonstrates multiple flaws in the system. Dec 26, 2016 at 16:11
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    @DrunkenCodeMonkey Hashing doesn't protect against counterfeiting or invalidating, which is what Thunderforge was suggesting. You just hash your wood ball and add it to the database to counterfeit, or remove a valid wood ball from the database to invalidate. Hashing protects from reading and duplicating passwords, but why would you do that with the wood ball? Much easier to simply add a new ball than try to duplicate an existing one.
    – Kevin Fee
    Dec 26, 2016 at 16:12

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