These are great improv blocks and you can make them any size you like. For you background fabric you want to start with a square the same size as you’d like your finished block to be. I decided to make a 6.5 inch block for this tutorial so the fabric requirements reflect that. For the diagonal strip measure the diagonal of the fabric and add a couple of inches.
One 6.5 inch square of fabric.
Two strips of fabric at least 9.5 inches long and between 1-2.5 inches wide
I have used fabrics designed by me and printed by Prinfab on their cotton poplin fabric. Prinfab is a British fabric printing company which offers 18 different types of fabric for you to print your designs on.
Seam Allowance – 1/4 an inch
Place your long strip along one of the edges of your cut (ie. the long edge of one of the triangles) and sew into place using an quarter inch seam.
Press your seam, I press to the darker fabric – in this case the red – but if you prefer to press your seams open you can do that instead.
Sew the other side of the strip to the other triangle as per instructions above.
Cut another almost diagonal line across the block from one side to the other. Sew your second strip into place with a quarter inch seam.
Your block will now no longer be square, trim the block back down to a 6.5 inch block. Then start your next one, why not make the angles different on each for a real improv effect?