Chris Heuser


The team will walk into a theatre to see a roughly 3 minute video playing on a loop with roughly 30 seconds between loops.


This is a "change blindness" puzzle (see this video for an example). In the video, an Illudo and a "volunteer from the audience" demonstrate how to perform a magic trick. None of the trick is relevant to the puzzle. None of the discussion (or any sound of any kind) is relevant to the puzzle. During the trick demonstration, 6 objects will sneakily change while out of view. The point of the puzzle is to identify the 6 objects that changed and the order they changed in. The 6 objects that change (in order) are:

  1. ** C**ALENDAR
  2. C** H**AIR
  3. CH** A**LKBOARD
  4. PLA** N**T
  5. BACK** G**ROUND
  6. HOODI** E**

With this information, indexing by order (sometimes called a diagonal extraction, in bold above) gives the final answer: CHANGE.

Side Notes:

  • We have avoided using any "number words" (like 'first', 'two times', etc.) in the discussion.

  • The card that plays a major role in the trick is a 6. This is not required, but it can serve as a hint towards how many changes they will need to acquire.


Common sources of issues:

  1. Not knowing how many changes to look for.

    1. There are two keys in place to indicate this:

      1. The card that plays a major role in the trick is a 6.

      2. There is a zoom in and a zoom out for each change. Many teams have used this as an indication of how many changes to look for.

  2. Not identifying the correct canonical names for each object.

    1. The 2 most difficult are referenced in the discussion: BACKGROUND, and HOODIE

    2. It is common to use CHALKBOARD, BOARD, or BLACKBOARD for that object. All 3 have an "A" in the 3rd spot and will work just fine.

    3. All 6 correct versions of the words are partial answers with "Keep going" as a response

    4. It is common to refer to the BACKGROUND as a "BACKDROP", which is a problem. The word "BACKGROUND" is used distinctively in the discussion as mentioned above in an attempt to help with this.

  3. Noticing that the plant might have changed, but remaining unconvinced.

    1. I'm not sure how to help with this, the plant is quite different! This has always ended the right way on its own - but I'm mentioning it just in case.
  4. Not knowing what to do once the 6 words have been acquired.

    1. Most teams have not had major issues with the last step, but hinting towards paying attention to the order they occurred in is a good way to help this without giving it completely away.

    2. If you want to hint further, I would suggest asking if they have any numbers available to potentially use as an index.