Here's the video version of the instructions:
Step 1: Clean off the paint
However, skipping this step altogether makes it quite hard to see what you're doing in subsequent steps.
By far the easiest time to do this is when the can is still full and sealed, because the liquid inside will support the walls as you press on them with the abrasive.
Step 2: Cut the can open
This should leave you with a rectangle-shaped piece of thin metal.
The edges may be incredibly sharp and jagged. Please be really careful!
Trim off the jagged edges of the rectangle, but try not to remove too much material.
Step 3: Tape the metal to a slightly springy board
Step 4: Mark out the net of the box
- starting with a two-inch square right in the middle, then a four-inch square surrounding it, followed by another (approx) 5 inch square surrounding that.
Extend the lines right off the edge of the metal in both directions - when you're done, you should end up with a quite complicated-looking grid pattern (take a look at the pictures for details).
The above dimensions are based on a tall 440ml can - if you're starting with a smaller one, you might need to scale things down to fit the available materials
Step 5: Inscribe patterns in the top and sides
You can even do lettering, but as this will be the inside surface of the box, you'll need to write it backwards.
Step 6: Outline the raised pattern
Turn it over so you're working on the side with the raised pattern.
Using the ballpoint pen, inscribe a line around the inside and outside edge of all the raised patterns.
This takes quite a while and seems laborious, but it's worth it in the end, so keep going...
Step 7: Re-impress the original embossed pattern
With the ballpoint pen, firmly retrace the entire original pattern.
This process of inscribing, outlining, then re-inscribing the pattern creates a much sharper relief for the box decoration.
Step 9: Scribe the corner pieces
Using the ballpoint pen and a straight edge, inscribe diagonal lines into each of the corner pieces, running out radially from the centre.
Step 10: Fold along the creases to form the box
The diagonal corners fold inwards as the sides fold down.
Once the sides are folded to an angle of 90 degrees vs the top, the folded-in corner pieces can be pinched flat and pressed in pairs against the inside.
Step 11: Fold in the tabs
This performs two functions - the folded tab secures the corner pieces in place, holding the box together, but also, the folded edge means the finished box should have no exposed sharp edges.
Repeat for all four tabs and the box is finished.