Supplies: 1.5" strips (I used 6 sets for this), 1/4" foot, rotary cutter and cutting mat, quilter's ruler with 45 degree markings.
Start with three strips - these are each 1.5" wide. For this your 1/4" foot is your best friend, you want equal seams for this so that everything will match up nicely after cutting.
Iron the seam under the dar side. I iron from the top - with this method, the seam won't show through the white.
Then add the second strip to the other side of the white.
Same deal with the ironing here, have the seam hide under the darker fabric.
Here you can see the 45 degree marking lined up along the side edge of the strip.
This is a more wide view of the same set up. The 45 degree marking is along the side of the strip. At this point. Slice off that end to start making the right triangles.
Flip the ruler to the other end, to the other 45 degree marking to line of on the other side of the strips. The already cut edge and the edge of the ruler should form a 90 degree corner. Keep doing this down the length of the strip. I was getting 12-13 triangles per strip depending on how close to the edge I started.
And here we have 60 (of 72) triangles arranged into blocks then rows. These haven't been stitched up yet, but that's coming shortly. I just thought I would give the step by step instructions for anyone else who wanted to try this. It's very easy, but it's a visually striking pattern. I used almsot exactly half a yard of the blue swirls fabric which is the Alexander Henry Pirate Island Salty Sea. I'll be putting Ed Emberley's Happy Drawing Too Octopus in Deep Blue around it as a border with white corner stones.