It sounds like you are describing a method for making a cat's cradle unit. Your photo shows one half of the unit, then you'd typically add the large HST to complete the unit. But if these are to be your border, you're not making the whole unit, just the part shown, which I've seen called a 'wing unit' by Bonnie Hunter in some of her mysteries. I've only made this with a square and two triangles -- can't quite picture how using squares and rectangles together would yield the unit shown.