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.
Make a valley fold, vertical, by bringing the left edge along the valley fold marking the vertical axis of symmetry.
Well crease the fold.
additional information
- You get 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 the bottom edge up to the top edge. Well crease the fold, 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 initial 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 folding to the top right corner. Crease the fold well.
additional information
- The right flap now has a right-angled triangle, with the right tip (90° angle) 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 symmetry axis. 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 folding to the bottom right corner. Crease the fold well.
Step 8.
Rotate the folding on the horizontal plane by 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 base rectangle by a vertical hinge edge on the right.
Step 9.
Repeat the manipulations described in steps 6 and 7.
additional information
- a triple-layer fold is obtained.
- on the table side, a vertical rectangle.
- in the middle, two free triangular flaps, each connected to one of the lengths of the rectangle underneath, by a hinge edge.
- the vertices of the two triangular flaps meet at the center of the fold.
- Each of these two triangular sections has, at 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 lower edge and the upper edge of the fold.
Step 10.
Form a valley fold by bringing the top edge of the fold down along the valley fold marking the horizontal axis of symmetry.
Crease well and then unfold.
Step 11.
Form a valley fold by bringing the bottom edge of the fold up along the valley fold marking the horizontal axis of symmetry.
Crease well and then unfold.
additional information
- We now have three horizontal valley folds: a lower, a central, and an upper one.
Step 12.
Form a valley fold by bringing from top to bottom, the upper edge of the fold, along the lower horizontal valley fold.
Well crease the fold then unfold.
Step 13.
Form a valley fold by bringing from bottom to top, the lower edge of the fold, along the upper horizontal valley fold.
Well crease the fold then unfold.
Step 14.
Form a valley fold by bringing from top to bottom, the upper edge of the fold, along the upper horizontal valley fold.
Well crease the fold 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.
Well crease the fold then unfold.
additional information
- We now have seven horizontal valley folds, dividing the height of our folding into eight horizontal panels of the same width.
- Let's name our 8 panels from top to bottom as panels 1 to 8.
Step 16.
Flip panel 8 from bottom to top over panel 7, using the valley hinge fold that connects them.
Then form a horizontal valley fold by bringing the top edge of panel 8 down along the hinge edge that connects it to panel 7. Make sure to crease it well.
additional information
- The lower part of panel 7 is now triple thickness and begins to form an accordion.
Step 17.
Flip panel 7 from bottom to top over panel 6, using the valley hinge fold that connects them.
The accordion section is now between panel 7 and panel 6.
Then form a horizontal valley fold, bringing the top edge of flap 7 along the hinge edge that connects it to flap 6 from top to bottom. Crease the fold well.
additional information
- The lower part of flap 6 is now thickness 5.
- The accordion has returned to the ceiling side.
Step 18.
Tilt flap 6 from bottom to top over flap 5, using the valley hinge fold that connects them.
The accordion part is between flap 6 and flap 5.
Then form a horizontal valley fold, bringing the top edge of flap 6 along the hinge edge that connects it to flap 5 from top to bottom. Crease the fold well.
additional information
- The accordion has returned to the ceiling side.
Step 19.
Tilt flap 5 from bottom to top over flap 4, using the valley hinge fold that connects them.
The accordion section is located between panel 5 and panel 4.
Then form a horizontal valley fold by bringing the top edge of panel 5 down along the hinge edge that connects it to panel 4. Make sure to crease the fold well.
additional information
- The accordion has returned to the ceiling side.
Step 20.
Flip panel 4 from bottom to top onto panel 3, using the valley hinge fold that connects them.
Then form a horizontal valley fold by bringing the top edge of panel 4 down along the hinge edge that connects it to panel 3. Make sure to crease the fold well.
additional information
- The accordion has returned to the ceiling side.
Step 21.
Flip panel 3 from bottom to top onto panel 2, using the valley hinge fold that connects them.
Then form a horizontal valley fold, bringing the top edge of flap 3 along the hinge edge that connects it to flap 2 from top to bottom. Make sure to crease the fold well.
additional information
- the accordion is back on the ceiling side.
Step 22.
Flip flap 2 from bottom to top onto flap 1, using the valley hinge fold that connects them.
Then form a horizontal valley fold, bringing the top edge of flap 2 along the hinge edge that connects it to flap 1 from top to bottom. Make sure to crease the fold well.
additional information
- flap 1 now has a hinge edge that connects it to our accordion.
Step 23.
Turn the folding from right to left.
additional information
- flap 1 is on top, and its hinge edge connects it to our accordion underneath.
Step 24.
Form a horizontal valley fold, bringing from top to bottom, the upper edge of flap 1 along the hinge fold that connects it to the accordion. Make sure to mark the fold well.
additional information
- the result is a 16-flap folded accordion, with 8 mountain folds and 7 valley folds alternating.
Step 25.
Using a semi-rigid wire (like a freezer bag closure), tie the accordion at the initial mark of the central vertical axis.
Step 26.
On either side of the tying, unfold the accordion flaps to shape the butterfly.
additional information
- the free ends of the semi-rigid wire will form the butterfly's antennae.