First, take two triangles of different fabric. We'll call them A and B.
Take the second piece, turn it upside down, and put on top of the first one as shown on the image below.
Shift the piece B (up and to the left) 1/4" away from the lower corner of the piece A. Both pieces will have their corners sticking out. Once aligned, sew the pieces together as indicated by the black line, which is also 1/4" away from the edge.
Unfold the pieces.
Cut the edges off (optional).
This is what the final composite diamond shape should look like.
Let's take this one step further and combine diamond shapes. Take two pieces of fabric. Again, we'll call them A and B.
Turn the piece B upside down, place it on top of the piece A, and shift it to the side. Once aligned, sew the pieces as shown with the black line. The line where you sew should be 1/4" away from the edge.
Unfold the pieces and cut off the end as shown on the image below.
This is what the final diamond should look like.
Things become really interesting when we use composite diamonds. For example, if we use two diamonds made of triangles as shown below:
and combine them using the same method. This is what we get:
Blocks like that take a lot of time and effort to craft, but can make a finished quilt look much more complex.
That's all for now. I'll cover more basic blocks and shapes in the future.
In the last issue, I mentioned that the difference in size between the original and final squares of half square triangles for 1/4" sewing margin should be 6/8". Since then, I received an email from one subscriber, Susan, where she said that she adds 7/8" instead and then trims the final square if needed. I guess that is a valid approach, so I just want everyone to know about it.
For 1/2 square triangles you must add 7/8" to get the square the size you want. 1/4" for each side seam and 3/8" for the 1/4" diagonal seam. The 1/4" is the measurement of the seam and the 3/8" is the measurement of the little rabbit ear that you cut off. If you want 2 3" finished '1/2 square triangles' from 2 squares you must cut the 2 squares at 3 7/8". When you cut diagonal, the straight side will actually be 3/8" smaller.