Dimple-Lock
[Revised Dec 1, 2008] This is a way to join two sheets without glue, along a common mountain-fold, at a single point. It uses the ‘dimple’ method I’ve been discussing in recent posts. It's a pretty tight lock; for two free-moving sheets I don’t think I’ve seen one as tight. 1. Valley fold through both sheets, about 2 or 3 cm from the edge to be joined. 2. Remove one sheet, turn it over. 3. Reinsert. 4. Make a diamond dimple through both layers. (Put your hand between the layers from behind, and press in with a finger.) Sharpen the folds, both the diamond mountain fold and the valley at its center. 5. Close the dimple, sharpen the triangles that form next to it. (The far corners of the triangles are arbitrarily located so you may as well align one of them with the cut edge of the overlapping sheet and the other symmetrically). Step 5 will also make both sheets conical. It is best if the cones of both sheets are oriented in opposite directions--otherwise you will have to invert one o...
