Download the following pattern as a PDF and print it out.
Place it on a piece of card – or, better still, a felt mat – and cut out the two basic shapes.
Then put the pieces together as follows:
Coat both sides of the top section with glue and join them together.
You can also simply stick them together.
You will receive this basic form.
Now make holes in the places shown.
You can also use a hole punch for this.
Then thread elastic bands through the holes and tie them in a knot.
You can now secure your mobile phone, with the display facing inwards, in the front elastic bands.
Pull the rear elastic band tight enough so that the assembly doesn’t fall off when you put it on. If you only intend to use it whilst lying down, you’ll need practically no tension at all.