Bargello started out as a long-stitch form of needlepoint. You might find a book of patterns in the needlepoint section of your library. I have transferred some patterns from a needlepoint book to graph paper for quilts, letting each square of the needlepoint pattern be a square on the graph paper, then converting them to 2" (finished) fabric pieces. Once you understand the basic method of piecing bands of fabric and cutting slices, you can try this.