You put together 2 strips, right sides together, and sew a 1/4" seam on both sides of the strip:
The cut at a 45 degree angle. A ruler with these markings make it easier. I am using 3" strips here, and it will yield 3.5" squares. There will be a little waste on the end with the first cut.
Keep cutting at a 45 degree angle, alternating directions. The cool part is you will be cutting off those pesky little dog-ears while you're at it.
You'll end up with thirteen 3.5" squares, from a 44" strip of 3" wide fabric.
Finger press them to the darker side, to get lots of these:
Another nice thing is that the diagonal seam is not on the bias, and will not stretch. This makes the block a little more stable.
Give this technique a try- it's really a time saver. I made hundreds of these little guys in no time. And they're much more accurate than cutting all those pesky triangles before you piece them together.