quiltsRfun, I wouldn't do them over, I expect they will be just as striking the way they are, truly. Yellow and neutral are both light colors, if at mattered the green would be at the top or bottom.
Stitch
this is my 4th mystery and based on past experience I would fully encourage you to get and use the rulers.
Be sure your fabric is pressed (and starched if you are a starcher, I am) and pay attention to Bonnie's instructions about right sides together, or right sides stacked.
Some of the members have said JoAnn's do have the rulers and they used their 50% coupon.
Mother is on the rampage this morning so I haven't cut anything yet, need to concentrate
