If you are talking about the white block with a square in the middle that's easy peasy. This is just one of the ways of making this block, and this is how I still do it.
You start with with the center which is square (red). From contrasting fabric (white) make two squares of the same size as the red square and sew them to the top and the bottom of the red square. From the white fabric make the side strips that are the same width as the starting square and that are as long as the three squares joined together. This is just one of the ways of making this block, and this is how I still do it
For Example:
3"x3" square - make two white and one red. Sew together in order w-r-w
3"x 8 1/2" - cut two white strips and join to the sides of the first pieced strip. (this would be the measure if you use 1/4" seam.
See, easy peasy!