I gave myself a rule that I couldn't buy additional fabric for the backing, so I pieced it together from various leftovers used to make the top, as well as the yard of so of the frog fabric that I happened to have on hand. There's actually a reason for having frogs on a quilt in honor of our cats. One day, when she was about a year-and-a-half old or so, our younger cat came running in with an excited squeal. Dangling from her mouth was an enormous dead frog!
Husband: Is it real? Me: I don't know--do you think it's real? DH: I don't know--what do you think? Me: I have no idea. How about if you find out? DH's pronouncement (upon closer examination): I am afraid it is real.
*Yuck!* I sent DH to retrieve and dispose of the dead frog. When he really had to get close to it, he discovered that it was made of rubber! So much for DH's talents as a naturalist. I don't know whether our cat stole the frog from some neighborhood children or if they gave it to her, but she was so excited and proud of herself for killing an enormous rubber frog. Oh, the mighty hunter!