A woven fabric is said to be cut on the bias, or cross-grain, when the fabric's warp and weft threads are at 45 degrees to its major seam lines. Every piece of woven fabric has two biases, perpendicular to each other. Non-woven fabrics such as felt or interfacing do not have a bias.
To make a triangular fringed shawl, choose a wool fabric that is about 60" wide or more. You will need a square of fabric, so be sure to purchase two yards. Remove the selvage on the fabric and trim it to be a square. Woven fabrics can be ripped along the grain to get a straight edge. Use a rotary cutter and ruler to cut the fabric diagonally, at a 45 degree angle, through the square of fabric.
You can use one of the bias cut triangles as your shawl or you can cut on the bias in the perpendicular direction to your first cut and seam the four triangles together. Overlap, about a half inch, each connecting edge to the adjacent triangle's edge and machine sew each seam with two straight stitches about one quarter inch apart. This will make your shawl a bit larger.
For the leather fringe, follow the same instructions as the scarf. For a 60" wide piece of fabric, my resulting bias cut triangle needed about 50 tassels along each side, starting from the point of the 90 degree angle.