Try this grid assembly technique when you need lots of identical triangle squares. By drawing it directly on the reverse side of the lightest triangle square fabric this is really quick and easy
Refer to your pattern or calculate the finished size of the triangle squares. Add 7/8" to that size to determine length and strip width. I tend to add on an inch I can’t be doing with fiddling with 1/8 “, it’s easy to trim it off.
Determine how many squares you need. Each square in the grid produces 2 triangle squares.
To calculate total strip length, multiply the grid size by the number of squares required. Use shorter lengths of multiple strips if necessary to make the best use of your yardage.
Cut strips of the two fabrics chosen for your triangle squares, remember add on the 1” or 7/8”
Use a pencil to mark square segments along the length of the strip. The distance between each vertical line is the same as the width of the strip. Straighten the edge of the strip before you mark to make sure all vertical lines are perpendicular with the top and bottom of the strip.
Continue marking until all squares are joined by diagonal lines moving in an up and down manner along the strip.
Place your two strips of fabric right sides together match edges. Pin the strips together along their length to keep them from moving apart.
Begin sewing at one end, placing your seams a scant 1/4" from the diagonal line that connects squares. Use your 1/4" presser foot to gauge the distance. Stop sewing and turn at each corner to change directions.
This image shows the dark side to show the stitching line as it wont show on the cream side.
Repeat to sew a seam a scant 1/4" on the opposite side of the original diagonal lines.
Place the units on the ironing board, darkest triangle up. Press seam to the darker fabric
Trim to required size and to square up if necessary
right sides together and stitch either side of the diagonal line easy peasy lemon squeezy