I experimented last night with a 3-d pinwheel block just to discover I don't like it at all. Atleast not that version.
It sounded pretty simple - no 1/2 square triangles. It called for 4" squares. I used 5" - no big deal. For example, you have 8 4" squares; fold 4 of those in 1/2 triangular twice so they are small triangles now with only 1 raw edge. Then place them on the unfolded 4" squares - repeat for all 4 so it makes a pinwheel.
WELL, looks great layed out until the sewing begins. I think they almost need to be basted prior to sewing the squares together. My center point of the pinwheel didn't match up at all.....humpf. THEN the 3-d pinwheel didn't lay as nicely as I hoped, even after ironing.
Oh well, nothing ventured - nothing gained, right?!
I'll have to post a pic of the "ugh" block tonight.