1. Fold bottom edge to top edge.
2. Fold top layer in half downwards.
3. Now fold the bottom up to top, and open again.
4. Fold bottom edge to this crease just made, then fold upwards again.
5. Fold the top of the paper downwards to the point shown. This point is just above the bottom fold.
6. Fold the bottom corners in to the bottom fold as shown.
7. Fold the sides in using the corner triangles as a guide. Open out again.
8. Using the creases, fold these creases within the rectangles as shown.
9. Open out the corner triangles and open up the fold along the crease shown. Model should now look like this.
10. Using existing creases, fold edge inwards and flatten bottom corner triangles as shown.
11. Fold top back down along existing crease.
12. Fold edges inwards, bringing corner triangles outward and down as shown.
13. Tuck corner triangles in on themselves.
14. Make creases as shown: top corners down to crease. Then open.
15. Holding the envelope at the points shown, bring this point down and inside the envelope, as shown by the arrows. The creases should guide the way. Flatten model.
16. You can close the envelope by folding the top down along existing crease and tucking in. Finished Bar Envelope.