How do you know what size to make a corner block such as a four patch or pinwheel in the corners of your project after the sashing is added?
I usually use 2 1/2 strips around the blocks then a 3in border and five in border.

If I understand your question, the block would be made the same size as the sashing or border. 3" border = 3" block in each corner. Hope this helps--if not maybe someone else will have the answer.

greensleeves is correct. and if you want a double border with a large square on the corner...add the width of both borders and make the square that big....obviously you need to add in the appropriate amount for seam allowances.

I agree with kttb.That will take care of your problem/question pab

Whatever the width of the sashing is.

Thanks everybody I will give that a try.