Sew the Pillow Cover
Place the whole bandana, right-side down, on the cutting mat, aligning it on the mat’s baseline.
Layer one of the half bandanas on top, with the correct side facing you. Insert pins at the corners to keep the pieces aligned.

Carefully lift the bandanas and turn so the pinned piece is at the top.
Layer the second half on top, with the correct side facing up. Line up the edges and corners, and pin them together.
I also added pins to the center edges to keep everything correctly aligned.

Line the pillow case up as best as you can on the baseline of the cutting mat.
Lay the quilting ruler at the two-inch line, and create a line. This will be the sewing line.

You can use an ink-dispensing pen made just for sewing, but I don’t have one, so I used a regular pencil.
Carefully pick up the pillow cover and rotate it 90 degrees to create the line on the next edge. Repeat until you have made the marked line on all four sides of the pillow cover.

Carefully lift the pillow cover, take it to your sewing machine, and sew along those marked lines.
After sewing all the way around the pillow case, you are done!
All that is left is to open the flap in the back and stuff the pillow insert into the new pillow case.

Make sure to push the pillow corners into the corners of the pillowcase, and you are done!