A while back I said I would post an idea I had for a shortcut for cutting and sewing the 1/2 triangle blocks if I got it to work.
Well.......IT WORKS!!
You can get 32 of the 3.5 inch blocks....easy peasy!   and you need to do this 5 times to get the 160 squares  you need for the  20 star blocks we are making.  I used my grid cutting mat and a roller cutter.
Here's what you do.
Layer your two fabrics right sides together, beige fabric up and cut five 16 inch squares.  (I started at the selvage side and cut three along the selvage edge and then two more just below. )   
Use your grid cutting mat to help with the next step.   Use  a quilt pencil or a #2 pencil and lightly draw on a 4 by 4 grid with the little squares measuring 4 inches.  4 across and 4 down.  
Next draw in only one direction of diagonal lines.  (I did mine from Upper left to lower right in each square.)   
Pin your fabric between the diagonal lines.
At your machine sew on either side of the diagonal lines with a scant 1/4 inch on each side.  (I sewed one side of the line and then turned the 16 inch fabric square and sewed the other side coming back.)  The opportunity to make longer seams helped me keep my seam lines straighter.
When finished with the sewing, take it back to your cutting mat and cut the grid lines into rows....each row with four squares.  Using your pencil lines, cut the rows into the four squares and then cut the diagonal lines. ( I was able to cut all the squares without moving anything because my mat will "grip the fabric as it is cut.)  
Voila...32 triangle squares to take to the ironing board.  
You will have little threads across the 90 degree corner of the indise squares... As I ironed, I used the point of my seam ripper to flip out the little thread so I could pull it out.
You can trim to the 3.5 inch square... depending on how "scant" your 1/4 inch is
I have to admit...I had already cut part of my squares and was really tired of having to cut out each 4 inch square. layer. Pencil line. Sew and cut.
This is so much faster.
Using that same stragegy, I cut the rest of my fabrics into ten  7.5 x 15 inch blocks.     Layer the fabrics right sides together.  You need 10 of these sets.    You will have some fabric left over.
Then I used my pencil to draw a line dividing it into two 7.5 inch squares.  Then drew the diagonals.  I pinned and at the machine only sewed the 1/4 inch seams on  each side of the upper left to lower right diagonal in both squares.   I then cut the line between the two squares, cut the line between the diagonal seams and then the other diagonal....making 4 diagonal triangles.   
At the ironing board, I ironed and then pinned each pair together....seamed them into a 4 triangle square.
Right now, I'm doing the little bit of trimming to get the 6.5 inch squares needed for the center rows.
I did take pictures of the process but we are getting a major ice storm and we always loose out power.  We are suppposed to get anywhere from 1/2 inch to one inch of ice accumulation.  So If the power is still on after we feed cows and draw up water for use during the outage, I'll try to post a few.
Sorry I didn't get this shortcut posted for those of you who have already cut your fabrics...but the shortcut will come in handy for later projects.