Yes you can do just parts of a block in chenille. You can make it yourself or buy it premade. If you wanted certain colours or to match the rest of the appliqué, I would make it myself. You can stack 3-4 squares of fabric on top of each other. Pin them together and draw lines on a 45* angle every 1/2 inches or narrower depending on how high you want the fuzzy. Sew down the line and then cut the strips apart. Before you fluff the strips, sew them down the stitching line in place. You can buy a chenille brush to fluff the chenille so it doesn't have o be washed and dried o fluff it. If you surf the net, I am sure there will be a youtube video.