An Origami Block D: In January 2007 Erik Demaine gave the Anderson Lecture at Denison. One of Erik's primary interests is folding problems, which was a big part of his talk. A main result is Given any collection of straight edges, there exists a flat folding and a line in that folding such that cutting along it results in the desired pattern of cuts. You can find many examples and papers on this subject on Erik's Folding and Unfolding Page. I have included a folding pattern (a pdf file) to produce the Denison Block D.

Instructions for folding and cutting (with one straight cut) the Block D:

  1. Print the pdf file from above for the Block D pattern.
  2. Cut out the large square containing the pattern. (You'll find it easier to fold.)
  3. The heavy lines are the cut lines: Do not fold on these.
  4. The thin solid lines are mountain folds and the dashed lines are valley folds.
  5. First fold the square in half along fold marked with the circled 1.
  6. Now make the fold marked with the circled 2.
  7. Crease with your fingernails the mountain and valley folds. You'll find it easier if you first crease everything as a mountain then go through and recrease the valleys. Make these creases as sharp as you can.
  8. Now comes the hard part: Make all these folds! This is difficult at first, but you'll find it easier with a little experience. I start with the folds in the upper right corner. Then make the fold along the "spine" of the Block D last along with the folds on the left. The result should have all the thick lines (the cut lines) on top of each other. Your result should look like this (click for larger photo):
  9. With scissors make one straight cut long the thick line, unfold and admire your Block D.