You need four quarter square triangles in graduating
colors, or colors of your choosing. You can EITHER...use this
triangle template. ..OR cut your triangles from 5-1/4"
squares which have been cut in half on both diagonals.--you'll need
just one of four different colors. Using the standard scant
1/4" seam, sew the triangles together, first in pairs. Press
all seams to darker sides. Then join those pairs to make the block's
center. This should measure 4-1/2". Trim if needed...