I do crazy quilt piecing on muslin foundation blocks. Cut the block the size you want it to be - then start with either a 3 sided or 5 sided center and just start adding strips all around (sorta like log cabin to put together) and there you have it. The sides will be ragged but you just turn the block over and rotary trim to the muslin size. Or if you have some ugly fabric you could use this for the foundation blocks or even old sheets. I use stitch in the ditch for quilting. The extra foundation material makes the quilt heavier than one without - sometimes I just put a backing on it and sometimes I use a thin batting. It's a good way to use up scraps.