This post continues the Letter Fold Series.
Once again, the pattern is designed for American Letter sized paper. This one may have to be modified slightly for A4 paper. (I have been too busy designing other models to try this out yet. Some of you people that use "normal" (international) sized paper will probably beat me to it. Please share.
The Double Wrap Letterfold is unusual in that the paper tucks in on both the front and the back sides. First we collapse the front, then we bend the flaps around to the back and, after a few minor adjustments, tuck them under each other in a clockwise direction. But I'm getting ahead of the folding procedure here.
There is a fair bit of pre-creasing but I won't apologize because this makes the collapse process relatively painless.
Just so that we are clear, the red unbroken lines are mountain folds and the blue and green broken lines are valley folds. The pattern should be readable after printing it on a black and white printer. Using the standard -..-..-..-..- mountain crease symbol makes it difficult or impossible to unambiguously decipher patterns with small crease lines. Marker creases and those which are not used in the collapse, but are necessary for obtaining essential creases are marked with dotted lines in a pale color - grey if it does not matter whether they are mountain or valley folds and pale blue-green or red-orange if it does matter.
Now we've got the preliminaries out of the way, let's get on with the interesting parts.
Begin by folding the longitudinal marker creases: half, quarter, eighth and finally, two lines on the sixteenth grid. Crease these hard because the rest of the model rests upon them.
Turn paper 90 degrees. Using the 16th creases fold the left side of the paper towards the center and then fold the right side of the paper over it. Turn the model over (colored side up).
Using just the two top layers crease a diagonal as shown. Bend the paper over to make a side wall (and a square). Repeat on the other end. Don't forget to refold the paper or you will get the reflected diagonal on the wrong side. Not good.
Open up the paper and put it colored side down. Re-crease (valley fold) the side walls, making sure that the crease starts at the top of the new diagonals and the center marker fold lines up. This should ensure that you have a square square rather than a sloppy faux one. :-) Do both ends, of course.
With the short sides on the top and the bottom, fold the left and right sides towards the center, as you did when you made the square, but this time it doesn't matter if you start with the left of the right flap because you are going to fold through all layers.
Do not turn the model over (which is what you did last time, right?). Valley crease a diagonal (through all layers) across the central rectangle from the top left to the bottom right. Don't fold the other the diagonal.
Open up. (Colored side is still down.) The central diagonal should be reflected on the sides.
Now refold the diagonal so that it extends from top to bottom. It will not quite intersect the corners. (See the crease pattern.)
O.K. guys, we are nearly to the easy part, because you have all the major creases by now.
You could try collapsing the model, clockwise, using the thick lines around the sides and the central rectangle as the base. However, I recommend creating those green creases first.
To do this, start with the paper, white side up, and short sides at the top and bottom. Got that? Bring the left side towards the center, using the thick red diagonal on that side and the thick blue crease that nearly bisects the corner. The top will start to come down towards the center. Make sure that the right hand side of the top flap lines up with the right hand side of the rest of the paper. Squash the left side out gently. That should make the green crease.
Repeat the process on the other side. This time do not unfold it. You have started the collapse process.
Continue folding down the sides around the base in a clockwise direction. If you creased everything firmly it should be very easy as those thickly marked side creases almost want to fold themselves. Ease out the final diagonal so that you have a four white wings as the picture shows. Only two sides meet in the middle; the other two are offset. The ones that meet along the central diagonal do not reach the sides so that the offset flaps have "tails".
Ta da! You have the front completed.
Bend over the flaps to the back of the model. Turn it over. Now we finish the back.
The two flaps with the white tails are complete. The other two flaps need to be narrowed so that they meet along the diagonal. You will find the lines already there on one side. Re-fold them so that the other side is also creased. Fold any excess paper over the edge, unfold and tuck it between the layers of the point. (You can skip this step but it makes it easier to slot these flaps under the other ones during the final step. It also makes the back look neater by removing any little bits that ruin the nice straight lines of the folded flaps. )
The last bit is easy. Beginning with one of the white tail flaps, fold the flaps towards the center in clockwise direction, one over the other. Tuck the final flap (a pointed one) under its neighbor. And there it is - completed. If you have make one you are happy with then photograph it and send a copy to this Blog. Be famous!
Now unfold the model, write something nice between the crease marks on the white side , fold it back up again and send it to someone you like.
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I will eventually make diagrammed instructions. These are time consuming and I am considering selling them, for a reasonably small amount, to those who can't follow crease patterns and my picture-free verbal instructions.
