Flip the canvas over and tape one end of the yarn onto the back using the masking tape.
Turn the canvas back over and tightly wrap the yarn around the canvas in a random pattern. At times, you may need to tape the yarn in place on the back. For example, near the corners.
Once you are satisfied with the way your canvas is wrapped. Place the canvas front side up on a piece of plastic or cardboard outdoors or in a well-ventilated area.
Wear a mask, spray the canvas with different color spray paints.
Leave the canvas to dry completely, preferably 3 hours.
Cut the string off and remove the tape from the back.
Find a location for your masterpiece, hang it and enjoy!