stack and whack or Kaleidoscope, depending on how it was cut. OBW assembles the pieced blocks without any background or sashing (and uses 6 triangles to make a hexagon). Most stack and whack's I've seen use 8 triangles or diamonds to make some type of star, use a background fabric to fill out the block to be square, and most of the time use sashing between the blocks.
Stack and Whack, OBW, and 4 patch posey (uses 4 squares to make a block) are variations of a Kaleidoscope quilt, which uses fabric repeats, turned at an angle, to make the block.