Material: a semi-rigid wire, like a freezer bag closure wire.
Step 1.
Take a square sheet, lay it flat on the table, with the bottom edge horizontal.
additional information
- The corners of the square are: top left, top right, bottom right, and bottom left.
Step 2.
Make a valley fold, vertical, by bringing the right edge over to the left edge.
Crease well, then unfold.
additional information
- You have just marked the vertical axis of symmetry. It is a valley fold.
Step 3.
Make a valley fold, vertical, by bringing the right edge along the valley fold marking the vertical axis of symmetry.
Crease well.
Step 4.
Form a valley fold, vertical, by bringing from left to right, the left edge along the valley fold marking the vertical axis of symmetry.
Crease well.
additional information
- You obtain a vertical rectangle with at the front, two free single-thickness rectangular flaps (one right and one left) each connected to the base rectangle by a hinge edge.
- The junction of these two flaps forms a slit along the vertical axis of symmetry.
Step 5.
Form a valley fold, horizontal, by bringing from bottom to top, the bottom edge onto the top edge. Crease well, then unfold.
additional information
- You have just marked the horizontal axis of symmetry.
- The intersection of the horizontal valley fold and the vertical slit determines the center of the starting square sheet.
Step 6.
Place the index finger of the left hand on the vertical slit, just below the intersection with the valley fold of the horizontal axis of symmetry.
With the other hand, take the top left corner of the right flap, and bring it outside the background rectangle, forming a valley fold connecting the central point of the fold to the top right corner. Crease well.
additional information
- The right flap now has a right triangle, whose right tip (90° angle) is outside the background rectangle.
Step 7.
Place the index finger of the left hand on the vertical slit, just above the intersection with the valley fold of the horizontal axis of symmetry.
With the other hand, take the bottom left corner of the right flap, and bring it outside the background rectangle, forming a valley fold connecting the central point of the fold to the bottom right corner. Crease well.
Step 8.
Rotate the model on the horizontal plane, half a turn clockwise, so as to bring the front left flap to the right.
additional information
- The front right flap is a rectangle, with a smooth surface, connected to the background rectangle by a vertical hinge edge on the right.
Step 9.
Repeat the manipulations described in steps 6 and 7.
additional information
- You get a triple-layer fold.
- On the table side, a vertical rectangle.
- in the middle, two free triangular flaps, each attached to one of the lengths of the rectangle below, by a hinge edge.
- The vertices of the two triangular flaps meet at the center of the fold.
- each of these two triangular flaps carries on the front two triangles, one of whose sides connects the center of the fold to one of the corners of the base rectangle.
- The goal of the following steps is to create 7 parallel valley folds evenly spaced between the bottom edge and the top edge of the fold.
Step 10.
Create a valley fold by bringing the top edge of the fold down along the valley fold marking the horizontal axis of symmetry.
Well define the fold then unfold.
Step 11.
Form a valley fold by bringing the bottom edge of the paper from bottom to top along the valley fold marking the horizontal axis of symmetry.
Make sure to crease well, then unfold.
additional information
- There are three horizontal valley folds: a lower one, a central one, and an upper one.
Step 12.
Form a valley fold by bringing the top edge of the paper from top to bottom along the lower horizontal valley fold.
Make sure to crease well, then unfold.
Step 13.
Form a valley fold by bringing the bottom edge of the paper from bottom to top along the upper horizontal valley fold.
Make sure to crease well, then unfold.
Step 14.
Form a valley fold by bringing the top edge of the paper from top to bottom along the upper horizontal valley fold.
Make sure to crease well, then unfold.
Step 15.
Form a valley fold by bringing from bottom to top, the lower edge of the fold along the lower horizontal valley fold.
Crease well and then unfold.
additional information
- We now have seven horizontal valley folds, dividing the height of our folding into eight horizontal panels of equal width.
- Let’s name our 8 panels from panel 1 to panel 8, starting from the top to the bottom.
Step 16.
Flip from bottom to top, panel 8 over panel 7, using the hinge valley fold that connects them.
Then form a horizontal valley fold by bringing from top to bottom, the upper edge of panel 8 along the hinge edge that connects it to panel 7. Crease well.
additional information
- The lower part of panel 7 is now triple thickness and begins to form an accordion.
Step 17.
Flip from bottom to top, panel 7 onto panel 6, using the valley hinge fold that connects them.
The accordion part ends up between panel 7 and panel 6.
Then form a horizontal valley fold, bringing the top edge of panel 7 from top to bottom along the hinge edge that connects it to panel 6. Crease well.
additional information
- The lower part of panel 6 is now thickness 5.
- The accordion is back on the ceiling side.
Step 18.
Flip from bottom to top, panel 6 onto panel 5, using the valley hinge fold that connects them.
The accordion part ends up between panel 6 and panel 5.
Then form a horizontal valley fold, bringing the top edge of panel 6 from top to bottom along the hinge edge that connects it to panel 5. Crease well.
additional information
- the accordion has returned to the ceiling side.
Step 19.
Tilt from bottom to top, flap 5 onto flap 4, using the valley hinge fold that connects them.
The accordion part is now between flap 5 and flap 4.
Then make a horizontal valley fold, bringing from top to bottom the top edge of flap 5 along the hinge edge that connects it to flap 4. Crease well.
additional information
- the accordion has returned to the ceiling side.
Step 20.
Tilt from bottom to top, flap 4 onto flap 3, using the valley hinge fold that connects them.
Then make a horizontal valley fold, bringing from top to bottom the top edge of flap 4 along the hinge edge that connects it to flap 3. Crease well.
additional information
- the accordion has returned to the ceiling side.
Step 21.
Flip from bottom to top, panel 3 onto panel 2, using the hinge valley fold that connects them.
Then form a horizontal valley fold, bringing the top edge of panel 3 down along the hinge edge that connects it to panel 2. Make sure to creases the fold well.
additional information
- The accordion has returned to the ceiling side.
Step 22.
Flip from bottom to top, panel 2 onto panel 1, using the hinge valley fold that connects them.
Then form a horizontal valley fold, bringing the top edge of panel 2 down along the hinge edge that connects it to panel 1. Make sure to crease well.
additional information
- Panel 1 now has a hinge edge that connects it to our accordion.
Step 23.
Turn the model over from right to left.
additional information
- flap 1 is on top, and its hinge edge connects it to our accordion which is below.
Step 24.
Form a horizontal valley fold by bringing down the top edge of flap 1 along the hinge fold that connects it to the accordion. Crease well.
additional information
- the result is a 16-flap folded accordion, with 8 mountain folds and 7 alternating valley folds.
Step 25.
Using a semi-rigid wire (like a freezer bag twist tie), tie the accordion at the mark of the central vertical axis.
Step 26.
Unfold the accordion flaps on either side of the tie to shape the butterfly.
additional information
- the free ends of the semi-rigid wire will form the butterfly's antennae.