The front of this letter fold looks a little bit like the end of a gable roof, hence the name.
Here is the back view.
This is another very easy model. All it requires are a few cupboard folds, a hem and some corner bending. Then it gets folded in half and one end gets pushed under the hem of the other. Easy!
The crease that makes the model look like a roof is made by running a nail over the top sheet of paper to accent the outline of the end that has been pushed under it: a triangle with a flat top.
Usually the paper does not push all the way in so you get a little ridge at the bottom. Think of it as roof spouting!
The samples are made with American Letter sized paper but the pattern should work with A4 and probably with slightly different sized rectangles.
Here is the Crease Pattern for this model. This will help you create a letter fold with the colored side out and the gable roof end in white. If you want to reverse this and make one with the colored side accented at the top, then start folding with the colored side up.
If you cannot see the crease marks easily on patterned paper then fold most of the model from the white side and then reverse the creases before you do the final fold and tuck the ends together.