Wondering if it would work as a biscornu ......

Your pattern can be any thing and any size for a biscornu as long as your overall pattern/design is square. 


This is the key it must be square.


I often start with some sort of a border to make sure I have a square then work inside that border.

If you want your button to be fancy/ a feature of the centre of your Biscornu you will not require any stitching underneath the button as it will be lost ie hidden by your button.

There are some really pretty border patterns about and yes if you can create your own go for it

Yes you can make a thing of your corners by putting something into them like a star or flower or geometric pattern  or beads or sequins to emphasize the corners.  I've also used this method.

You don't even have to have the same pattern on both sides.  My bigger one in with the crocuses in the thread 'Show us your biscornu's has tulips on the other side.

There are no rules for what goes on your biscornu expect the IT must be square otherwise when you sew it together your corners will not be sharpe and defined. 

You can be as adventurous as you want   Make them as big or small as you want.  I've seen some that are made to sit upon.