I hate doing these so much now I couldn't even imagine cutting for one, or mulitiples in different fabrics. lol.. so basically, I never make singles... Here's the cutting adaptation for multiples....
cut a strip 6" wide and the full 45" width of the fabric, then do a 2 1/2" strip the same way. Sew them and turn them, cut the wide one in thirds and the narrow one in forths, and you now have enough for three, plus a spare elastic casing. (since I really do multiples, I cut four wide strips and three narrow so I come out even an even dozen, lol)
Remember, multiples are great for pinatas and party bags.
