patterns that are in public domain can be used by anyone for any purpose they want. there is a difference between using common blocks and using someones quilt design. it is what you do with the blocks you make that makes all the difference. there are tons of quilt designs that everyone uses, like log cabin block layouts; barn raising...it is when a person does something totally different and claims it as their own then chooses to share the pattern that the problem seems to come up. when you buy that pattern and make it 'their' way it is still 'their' design, you have to get their permission to show it, you can not 'share' the pattern/design...if your friend wants to make one too she has to buy her own pattern...