That was the first quilt I ever made, adapted from a baby quilt to double size. Simple enough pattern but I was a seamstress back then and oh my how those diagonals like to stretch when
ironed instead of pressed.
Take any size square you want. Cut squares of background fabric half the size (If you start with a 10 inch square, you would cut the background squares 5 inches) Draw a line diagonally on the background squares. Lay one background square in the upper left of the large square, sew along the line, flip and trim. Do the same for the lower right corner.
And Mr Google found a tutorial for x's and o's
https://quiltingtutorials.com/tutori...ting-tutorials