How tos of working on the Echo Chamber Quilt. All strips are cut 1 3/4" wide. When quarter inch seam allowances are used, the ending width of the strip should be consistent in size, and the recommended size using a 1/4" seam allowance is 1 1/4 inches.
You start with a basic 4-patch with darks and lights alternated (Scan 1)
Then you build a strip around the essentially resultant three-inch four-patch using light strips cut 3 inches, 4 1/4", 4 1/4", and 5 1/2" that encases your basic 4-patch. It should measure 5 1/2" square at this point. (Scan 2)
Then you echo the chamber on the two lower edges, leaving the 5 1/2" light and its 4 1/4" neighbor, open. the first edge dark measures 5 1/2", second and third measure 6 3/4" fourth and fifth measures 8", and the final outside sixth dark strip is cut 9 1/4", then sewn. If you cut exact measurements using a consistent 1/4" seam allowance your square will be right and you'll wonder why you ever did log cabin sewing any other way if you have done hit-and-miss all your life on them like I did before I wised up to "Oh! It's less trouble and saves you half your time if you precut strips before you start sewing!!!!!!!"
I swear, I have made 100 of these log cabin quilts, and I didn't really figure it out until about quilt #55. I've made 10 log cabin quilts just this year, tucking in one here and there every time I take 10 quilts down to the Charity bees, I like one or two of them to be log cabins, just because they're so wonderfully homey and cuddly to the person who gets one. It looks like someone worked their butts off making it too, because they did. After the 6th echo log, the square now measures 9 1/4".
Sew one square first and see to it that it measures out okay. The final square is 9 1/4" exactly, on all 4 sides. If not, your quarter-inch seam allowance needs work. Even when you have a 1/4" foot, sometimes your sewing is not consistent with the designer's 1/4", and you need to do something about it.
May I make a suggestion? First, be patient and be certain you have a seam ripper that can go under a two-millimeter stitch without ripping the cotton fabric. Press the seams outward before adding the next strip. It pays to do only one square first and waste a little thread, to get your measurement down pat. If you're still not sure, do another independent square. You'll know right away if you are measuring your strips first before adding them to your square. If the three-inch piece on the chamber is added to a side, and it's longer than the four-patch side, your seams in the 4-patch are likely too large. Aren't you glad you only did one instead of all 32?
I know how to rip 32 consecutive squares apart! I probably should have just put them in the senior-pillow stuffing bin for support quilts (all your strips and cotton threads are the best fillers for a tough-support pillow that a senior can use to elevate his or her feet and not go mushy on them. It really means a lot to those who have swollen feet at the end of the day to have a pillow that can be placed on the foot of the bed and will reliably elevate the foot 4 or 5 inches. It takes me 3 months of steady sewing to accumulate enough of that kind of scraps to stuff the pillows with. In a pinch, if the senior center is begging for sturdy pillows once the seniors tell them how good they make their feet feel at night, you can fill the demand by standing up at announcement time at church and requesting clean, used bath towels you can cut up and put in your pillows. The ones that don't have holes in them make good "batting" for the outside of the pillow that prevents pokies from protruding here and there making uncomfortable welts. Don't forget to tell them your pillow does not replace the wonderful care of nurses and their aides to change positions on the more indigent of the people in their care that prevents bedsores. All your hard work is for naught if that isn't done. Let them know their nursing care is more important than an old pillow, and you can bet your seniors will get the best tlc in the world. We mustn't forget to thank and promote the care giver when we can. They're the solid gold of good health for seniors, and that's not a statement, it's a fact. On I go
Oh, if you read the link description, it tells you the measurements or vague description of what to do. Just put your mouse arrow over the thumbnail, and the description will pop up in a short moment or two. Click on the thumbnail, and you can see the fabric surface textures better. Half the fun of picking the right strip to go here or there is varying the size of the patterns in a random way. For girls it's more fun than dressing a baby doll when you're 5 or 6. For guys, it would be a challenge to using everything you thought you learned in art school and opening a new world into management of surface texture. And if you never went to art school, well, just go right ahead. Just one thing: no ripping out bad decisions. Once you make the decision, that's where your skill is in time and space. It won't even hit you until after the quilt is done. Then you learn to be wiser on the next quilt. I always told my students, it's better if you make mistakes. You can correct mistakes next quilt. If you never made any quilt errors, you'd never learn what you should not have done and build a better construct the next time. Never hurts to get a tablet of quadrille paper in the office section where papers are purchased. It can make the difference in hating a design and loving it because you followed the plan and stuck to it with skill and assurance.
Also, it's not a master work with centers being up to 1/3" off here and there, oh, and did I mention it? Not all the squares are exactly the same size, but the average of them is a finished 1.25" (1 1/4").
Pushy, aren't we. 
