Holy Grail Project - Re-Usable Collapsible Cup from Sustainable Materials

Step 6 The Folding Commences

Getting the plastic sheet into a cylindrical shape is where the project begins to get a little tricky. As you know, the horizontal lines, and the lines at 60 degrees, are mountain folds, so I like to begin by folding these. Just crease each line firmly in the right direction, then open it back out . After you've done these, you have to try and flatten it back out and do the valley folds in the opposite direction. This is more difficult given the surface irregularity.

When you've got the whole sheet creased, you have to start accentuating the folds so the diamonds start to close up. This is easiest if you start at one of the acute corners and work your way across the sheet. As the pictures show, you end up with a tube that has a spiral gap down it's length.