So as I read your post, nanac, you are attempting to see what a quilt block would look like when the pieces are laid out. The tangram link looks promising that QuiltnNan posted. Also, there are lots of tutorials on line as to how to use Photoshop to make a mock up, but it sounds like you are looking for a more hands on approach. The only other option that comes to my mind for this would be using the shapes from English Paper Piecing. There are some free downloads for this. You could scan your fabric and print off your fabric using a printer then using that same piece of paper print off the EPP shapes. Cut out your shapes and arrange.