googled 12 inch and it came up as 4 6" blocks will be a 12" block so the pattern you are trying to make will be a 12" block do a test to be sure.
Cracker Quilt Pattern - Quilting -
Quilt Patterns - Learn How ...
Cracker Quilt Pattern ... groups of four blocks finish at 12" square. From mottled turquoise fabric, ... Sewing a Quarter Inch Seam Allowance; See More About: