To make them you need:
large squares of fabric (I used 24 inch squares of fabric.)
a sewing machine or hand sewing needle
a matching or contrasting color of thread depending on your preference
an iron and ironing board
Step 1: Ironing the Fabric
Depending on the type of fabric you choose you may need to use a damp pressing cloth for the ironing. A pressing cloth is just a washcloth or other small cloth that you dampen (not soaking wet, ring it out well) and lay on top of the item to be ironed while ironing. After ironing with the pressing cloth be sure to remove the cloth and iron the project cloth dry. If you are using a stiffer cloth you may need to use this technique when pressing the seams.
Step 2: Pressing the Seams
Lay the fabric right side down on the ironing board and fold down one half inch along one edge. Iron down that half inch.
Fold down a triangle at each corner and iron it flat.
Rotate the piece 90 degrees and repeat until you have finished all four sides.