Today's Modern Block is Blue Lagoon by Pat Sloan.
I adore this block, and not just because it has three of my favorite fabrics in it. It went together quickly and easily. I love the slight contrast of the blues. I think if you put a bunch of them together, there would be a cool secondary design with those half-square triangle blocks and the cornerstones.
I'm picturing a quilt where each block features a different color. Maybe where the color runs from one block to the next. It would also be a great leader-ender project.