In the quilt below, the hearts were sewn onto squares of fabric "on point." That means that the points of the square are on the top, bottom and sides, forming a somewhat diamond shape.

Sewing this quilt together was a tiny bit tricky, since it was sewn with the blocks facing diagonally.
Starting from the upper left corner, you would attach the sashing to the sides of the block. Then attach a red triangle to the sashing on each side. Then put that aside.
Then take the next diagonal row of blocks (made up of the dark blue heart block, the red square and the lavendar heart block) and add sashing strips between each of these blocks.
You will be sewing plain fabric to the sides of these blocks, as the cornerstones will be included in the sashing strips between the rows.
Add a half-square triangle to the end of each of these rows. This will make the sides of your quilt into a square or rectangle.
Next, make a strip of sashing to go between the first "row" of one block, and the second "row" of three blocks. This strip of sashing will include plain sashing plus your cornerstones.
As you sew, match the cornerstones in the sashing strip with the sashing between the blocks. That way, you will have nice square corners that line up. It also helps to stitch and press the seam allowances in opposite directions, so your quilt top lays flat.
Happy Quilting!
Penny Halgren
www.How-to-Quilt.com
www.TheQuiltingCoach.com