A bit of googling reveals these door sstops are quite popular. Having recently moved i too wanted to make my home as cozy as possible and so worked out a simply pattern for a rectangular cube door stop.
I chose to make mine 11cm x 16cm with a 2.5cm seam allowance. I made a velcro flap for the bottom and used an off cut to add a handle to the top.
I think it worked really well with some patchwork style material i found and my back room now has a really country cottage feel about it.
The pattern i have made i printed on A1 but you should be able to print out the separate sections and stick together the door stop pattern.
Download – door stop pattern