From your "chimney " fabric, the color your center block will be, cut a strip 2 1/2" wide by the width of the fabric. Measure off at 2 1/2" increments, and with your rotary cutter, cut as many center squares as you will need for your quilt.( This may take more than one 2 1/2" strip!)

 

 

Next, sew on a strip of your first dark fabric. Mark and then cut this in 2 1/2" increments as shown...

Pivot your center square/first dark combo so that  the dark piece is on the top. Sew on a strip of the first dark on the right side, as shown, butting up each block to the next as you go, just leaving a tiny space between them so you can cut them apart. Continue until all center squares are done. Cut these apart as shown. Check to make sure you are nice and square...

Pivot this one turn to the left, then sew on the next strip, which will be your first light fabric. Repeat the previous step...

Continue in this manner, turning one turn to the left, adding the next strip, cutting apart and checking squareness, until all five rows have been added to your block!!
1999 Marcia Hohn