I do love working without a pattern. But for the PMQG Habitat Challenge I adapted the shadow seams log cabin to create a 12 inch finished block.
I originally tried it with 3/4" shadow strips, like the original blocks I made with this technique, but there wasn't enough breathing room for all those loud prints. They were a jumble and the design was not coming through. The second time I cut my shadow strips at 1" instead (doubling their finished size from 1/4" to 1/2"), and liked it much better.
To make the block I used:
a 4.5" center square and
2" strips in varying prints, from 4.5" to 12.5" long
1" shadow strips (I cut two strips x WOF).
(To make it using the original 3/4" shadow strips you would use the same size center and cut your print strips 2 1/4" wide.) Photos and steps in the original post.