Kona cotton or the cotton poplin.
I made my butterfly pillow by cutting around the outer solid black line of the butterfly, about 1/4" to 1/2" away from the black line. There is a coordinating Hollyhock stripe in the Hollyhocks collection that works well with this design OR two yards of "Hollyhock Butterfly" will give you identical front and back for the project. After I cut out the butterfly, I pinned it, right side down, to a yard of Spoonflower Kona cotton (right side up) printed with the Hollyhock stripe and used that as my guide to cut out the Hollyhock stripe in the butterfly shape. Stitch around the perimeter of the butterfly, leaving a large enough opening for stuffing. After stitching, turn right side out and stuff with polyester fiberfill or your fill of choice. fabric - 150 dpi - basic repeat wallpaper - 525 dpi - basic repeat decal (large) - 210 dpi - centered gift wrap - 242 dpi - basic repeat