Paint the entire wall with latex paint in the background color. Allow the paint to dry then add another coat of paint. Allow this coat to dry overnight.
Measure the height and width of the wall. Use an online harlequin diamond calculator, such as the one available from the Silver Spoon Murals website, to determine your desired diamond shape.
Draw vertical lines the width of your diamonds across the width of the wall. Use a chalk line to mark the lines then follow up with a pencil and straightedge to create more permanent lines. Draw very lightly with the pencil.
Draw horizontal lines across the wall to mark off the height of the diamonds. Use the same chalk line and pencil method. You should now have a grid of rectangles on the wall.
Turn each rectangle into a diamond by measuring the width of the top and bottom edge then making a dot with a pencil to mark the center of the line. Do the same with the right and left edges of each rectangle. Connect the dots in a diamond design with the straightedge and pencil.
Tape off the edges around each diamond in the first vertical row. Paint each diamond in this row the first argyle color. Tape off the edges of the diamonds in the third row and paint them the same color. Paint the diamonds in each odd-numbered row on the entire wall. Allow the paint to dry completely before continuing.
Tape off the edges of the diamonds in the second vertical row and paint them the second argyle color. Do the same with every even-numbered row on the wall. Allow the paint to dry before proceeding.
Measure each diagonal line on the sides of the diamonds and mark the center point of these lines lightly. Draw a series of diagonal lines connecting these dots from the top of the wall to the bottom in both directions. You should have a series of diamond shapes, offset from the painted diamonds.
Paint a series of dotted lines on top of the penciled diagonal lines. Paint a line along the straight edge for 1 inch then skip the next 1/2-inch. Continue in this manner until you have dotted lines that cross the entire argyle design. Allow the entire wall to dry for 24 hours before you replace the furnishing in the room.