I am trying to find a pattern for a 12" Jewel Box block. I found one for 10" but I don't know how to adjust it to 12". I have been on the internet looking but no luck. Does anyone have one to share or I will buy or know where I can get on. Thanks

If it's the one with the 4patch and hst blocks, just make them (each 4p and hst) 3" finished (3.5" unfinished). That should work. :-D

You would cut the squares 2" and the Half Square Triangles 3 7/8". I would cut the HST's at 4" and trim down to 3.5".