As part of the pinwheel quilt, I took the fabric lengths and cut 4inch pieces in pairs from all colours, ensuring I have equal number of light and dark squares. As directed, I placed one light piece over one dark piece (right side of fabric facing each other) and drew a pencil line through the diagonal. I made sure I make pencil markings on the lighter fabric and stitch with a darker thread so I can maintain the 1/4 cm distance from the line. The squares look like this.
Learning: I realized that the number of exact 4 inch squares is directly proportional to the experience you have in cutting fabric. I am a beginner so none of the pieces came out perfect. But I am happy as I am learning new things.