I’ve recently been working my way through some of the blocks from the Moda Building Blocks pattern of 2014 (I jumped on the bandwagon late during a sale last November). Some of the blocks that I’ve tackled have required me to add triangles to the sides of square to create ‘square in square’ blocks, and it ocurred to me that this pattern, like many, has absolutely no guidance on how best to do this.
This block had a couple of squares in squares:
The first thing to think about is that the triangle you are adding will be longer than the side of the square. This is deliberate, due to how the 1/4″ seam allowance will work, but it can be a pain measuring where it should fall on the square. The easiest way is to start by folding the square in half in both directions and making a crease in the middle along the fold lines each way:
Now that you have your centre lines marked, you can place the long side of the triangle along the edge of the square and match the point to the crease you have just made:
I usually add my triangles so that they’re in opposing pairs, as I’ve found that makes for the most accurate results. Once finished, you should have a perfect square in square:
I hope that helps any of you that have been struggling with how to work this sort of thing out.