Video Tutorial

Scroll down for step-by step pictorial instructions, or watch the video below...

Pictorial Instructions

Start with the front of an old Christmas card - if it's not square, trim it into a square.

To make a box and a fitting lid, you need two squares, one of which should be about 5mm smaller than the other in both directions. The larger one is the lid - bear this in mind when selecting your card.

Find and mark the centre of the plain side by placing a rule across the diagonals and marking a light pencil line through the middle.

Fold one corner in so that the tip just touches the centre mark.

Press and smooth down the fold.

Fold the same edge in again, so that it touches the centre.

Press and smooth down the fold.

Unfold the card flat again

Repeat the double fold operation on each of the other three corners in turn.

You should end up with a diagonal grid of folds like this.

Cut carefully along the fold nearest the centre, stopping at the corner of the unfolded square in the middle.

Make three more matching cuts in as shown here - ending up with two pairs of parallel cuts.

Fold in one of the sides as shown - the corner into the middle and the edge folded up at a right angle.

Note how this creates two slim pointed tabs at the edges...

Repeat the above folding operation on the opposite corner.

Push the pointed tabs in toward each other.

Fold the remaining corners in over the top of the pointed tabs, securing them in place.

When you press all of the corners down into the bottom of the box, they should lock into place against each other.

No glue is required.

Repeat all of the above with the smaller square of card.

You should end up with a pair of boxes that just fit snugly together.

Size Of The Finished Box

The process of making these boxes is all about geometry really - so it's possible to calculate in advance the size of the box you want, then cut a piece of card to suit.

The length/width of the top square of the finished box will be one quarter of the diameter of the square of card from which it is made.

You can calculate this as one quarter of the square root of twice the square of one side of the card, however, in practice (and given the tolerances of manufacture here), this works out so that the edge length of the finished box is just a little more than one third of the edge length of the square of card from which it is made).

So...

Your card square needs to be about three times the size of the box you want.