Worked from the bottom up in a lace pattern that gradually decreases in scale and forms sharp points along the edges. The strong verticals formed by the centred double decreases in the lace pattern transition into ribs on a garter stitch ground. Concentric decrease rows gather these spokes together until there are no stitches left between them. The centre is worked in garter stitch with the last few stitches grafted together for a neat finish.