The clever folds that kept letters secret

Previously on HN:<p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26532134" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26532134</a><p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26555153" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26555153</a><p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=18420924" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=18420924</a><p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26338673" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26338673</a><p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26327888" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=26327888</a>

After watching the video I do not understand what prevents anybody from reversing the strip through the hole after drying it.

That&#x27;s a lot of faith in the strength of a small strip of paper, I&#x27;d probably rip the thing several times just trying to make it like the video<p>Did they have stronger paper back then?