I guess I haven't talked about how much I like the "twister". This quilt design goes right to a math teacher's heart...tesselations...M.C. Escher Ask my students...They all know his work.
You pick a square size (I first started with 10"...I have a pile of butterfly fat quarters and they cut up nicely into layer cakes) Use spray sizing and iron seams so that each row has seams going a different direction. That way they will nestle well together and corners will match. Piece them together in rows until you get a size you like. Add a border all around...mine was aboout 3.5". Then the fun part.
Take your quilt, lay the "twister" ruler (I purchased mine from http://www.quiltpatchlane.com/ )in the the upper left corner, matching seams with lines on ruler and keeping the "cs" in the lower right of the square. Cut around the square with your rotary cutter carefully. Keep working straight across, moving the ruler to the right, matching seams to the lines on the ruler. I found that as I cut each square I would reposition them on my design wall. Resew new squares being careful of the bias edges and the directions you are ironing your seams. Add borders as you desire.
Here is the picture of my first completed Twister top for 2011.