You would start out with a square or rectangle on the paper for the house, right? Then you would add a triangle on top for the roof, is that how you would draw a house? That’s how I did it, and still do!
That is exactly the pattern for these envelopes. But use more of a rectangle than a square for your base. It’s that easy.
via only deco http://onlydeco10.blogspot.com/2014/09/diy.html