You know those clear dividers you get when you buy the deeper Art Bin satchel containers.? They are smooth on one side, ridged on the reverse? They make great overlays! Since I have temporarily misplaced my pen that wipes off with water, I am using a dry erase pen (and being very careful not to smudge the ink!).
Now I am ready for my overlay,
These are a little out of proportion because the camera is at an angle, but you get the general idea of the four blocks I will be stitching now!