Algebraic wall clock implies its own answers with the time


Though the brain-jelly-beads of my amygdalian abacus have long been evaporated by the heady toll of ether huffing, even I can feel smugly self-congratulatory telling time with the Pop Quiz Wall Clock. No price unfortunately, but it would probably be expressed in a for-me-unsolvable diophantine equation anyway.

Pop Quiz Wall Clock [Official Site via Nerd Approved]

Join the Conversation


  1. i had a teacher in high school who had a clock in radians on the wall in his class room.

  2. No math classroom should be without one. Great! I wonder if it is a real chalkboard surface that you could write your own formulas on.

  3. My dad, a software engineer, prefers his binary clock. Mainly I think this is because it’s easier to confuse the heck out of non-geeks with one of those. (He was upset to find that a lot of his company’s younger hires can’t read it. He even gives them a hint to watch how often it changes.)

  4. #1,

    I was far more fixated on 7 or -6 o’clock.

    But that use of Pi representing an arbitrary precision number is annoying to my nerd sensibilities.

  5. As pointed out, 52 – (6^2 + 6) = 10. Or, 52 – (7^2 + 7) = -4. Or, 52 – 7^2 + 7 = 10. Addition and subtraction have the same precedence, so for heaven’s sake buy some parens Vanna. And yes, using an irrational number (pi) is really out of place….

  6. Yes, because this is an American clock. Of course, in European notation, it would be .001, because we use commas in place of decimals.

  7. @4: That’s because unless you know that the time is represented with two digits for each hours, minutes, and seconds, and that each individual digit is encoded instead of the total value, the binary clock you linked to is essentially unreadable. It seems like one of those things that was designed by a marketing guru who wished he was a geek.

  8. @9, ivan256

    According to the ThinkGeek product page the clock can be switched between BCD and “true binary” modes.

  9. @#7, Addition and subtraction may have the same precedence but they go left to right. Also, there are no parentheses for a reason. You solve the exponent then go left to right. It’s obvious that X corresponds to the usual number on the clock.

  10. @7 Anonymous
    Parentheses aren’t necessary in your example. You’re supposed to process operators of equal precedence from left to right (so your second equation is actually incorrect). The problem is, as omnifrog noted, that that particular quadratic has two roots.

    But in my opinion, the biggest problem with this clock (aside from 9:00) is that all of the expressions chosen are so banal and uninteresting. For example, at 1:00, the best they could do is the difference of two sequential integers? There’s really nothing interesting about those particular numbers, except gosh, they’re kinda big…

    What a wasted chance to use something much more elegant, such as the expression (famous from Euler’s identity): -e^(iÏ€)
    Or heck, even simply 0.999… (which is exactly equal to 1, no approximation necessary).

    I do like the concept of this clock, though.

Leave a comment

Your email address will not be published. Required fields are marked *