Surprise your friends with infinite chocolate: puzzle

Next time, when you meet Friday with friends who are not familiar with this puzzle (I'm sure a couple of them still exist), show them an endless bar of chocolate. To do this, find a chocolate bar with a ratio of 6 by 4 pieces, cut it, change some parts in places and get an extra square.

Explanation, if you do not know it or have forgotten for prescription, in the video under the cut.



How did it happen? The law of conservation of chocolate works, as does optical illusion, because it seems to us that the size has not changed. But in fact, a piece is not superfluous.
')


If you do not want to watch the video.