In Wikipedia's bibliography of Martin Kruskal it is said:

Martin, who had a great love of games, puzzles, and word play of all kinds, also invented several quite unusual origami models including an envelope for sending secret messages (anyone who unfolded the envelope to read the message would have great difficulty refolding it to conceal the deed).

Unfortunately, this is the only information in Wikipedia about Kruskal's secret message envelope.

Does anyone know the history of this envelope, or where I can find more information about it?

This envelope seems like a puzzle, since there may have been a clever trick to refold it.

  • 1
    $\begingroup$ This seems overly broad; this could be referring to any number of origami models and envelopes. You're going to have to be a bit more specific. $\endgroup$
    – Doorknob
    Jun 7, 2014 at 2:06
  • $\begingroup$ There are a couple things which would be helpful in order to make this post answerable. Your edit does help clarify why you feel this is a good puzzle, but it's still a little unclear whether it actually is. A little more information could help, though! You may want to address: how is the envelope made? What suggests it might be difficult to refold? As I'm not sure this question can be answered until more information is part of the question, I feel it's a good idea to put it on hold for now. Thanks for understanding! $\endgroup$
    – user20
    Jun 7, 2014 at 2:27
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    $\begingroup$ I have no problem with "I have heard of" questions. The more details that can be supplied, the better chance an answer can be provided. If there isn't enough info, there won't be an answer. Is that a disaster? I'll start a thread on meta, citing this. $\endgroup$ Jun 7, 2014 at 3:07
  • $\begingroup$ I didn't start a thread, I found meta.puzzling.stackexchange.com/questions/227/… that seemed on topic. $\endgroup$ Jun 7, 2014 at 3:25
  • $\begingroup$ That's fair, @Ross. I see your point, and I'm more than happy to step back from this and let it go to the community. $\endgroup$
    – user20
    Jun 7, 2014 at 3:38

1 Answer 1


It is really hard to find something on the Web about Martin Kruskal in relation to origami.

There is a link missing in Wikipedia, so maybe this information is just gossip.

If you want to see how to fold an envelope for sending secret messages, you can check out:

  1. This method for a hard-to-open envelope.

  2. This method and this method for kind-of-hard-to-fold-back envelopes.


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