Place the two beach towels together corner to corner. Trim off excess toweling if one towel is larger than the other.
Sew the outside edges together with the sewing machine.
Line up and measure out the shelf liners so that they fit the entire length of the towels. Cut enough to cover both sides of the towel.
Use the hot glue gun to glue the shelf liners to the towels.
Allow 10 minutes to dry and set.
Roll up the new gym mat and place a large rubber band around it to keep it together.