MaryMo -
The link is for instruction purposes only as there may be someone who has never made a D4P. Each month we will have a different theme so while the basic instructions will be the same, the colors, etc. will change.
For December, there is a lot more room for 'playing'. Please use one black/white square, one white/black square and two different bright colors that 'read' as solid. They can be any combination, by the way.
So, you are absolutely right. ". . . all four squares for the 4-patch are different fabrics." Very good observation on your part.
Hope that helps!
Jane