Think about the words in the challenge. You said it is "a one block quilt 24" x 30" . It does not say...make a small quilt using one quilt block design....what would you design if you made "one block" that was 24 x 30 size. I did a guild challenge one time that the theme was circles. Instead of manking a double wedding reig I did a piece showing the circle of life of the butterfly...the challenge only said circles. So think bout what the words say .