To start with, I suppose I should call this type of rug a 'radial rug' as it is knitted in sections from the outside towards the center. To create the round shape, each segment is shaped as a triangle. This is achieved by diminishing each second row by two stitches. For a rug of 60 stitches, each segment would contain 60 rows, gradually diminishing to two stitches, while the other stitches have remained on the needle (see instructions).
A rug constructed in this way offers amazing design possibilities, from using one color to a multitude of colors, from shades of one color to three or four different colors in a specific sequence. Visualize such a rug as a circle consisting of triangular segments, wide at the outside, coming together in a point at the center.
For the current project I propose to arrange the colors to get a gradient effect. Dividing each section in three or more parts, depending on the number of shades to be used, would do this. Three is a good number to start with. A rug of 60 stitches would have 20 rows of each shade. Shade number one would be rows 1 t0 20. Shade number two would start at row 21. By that time there are only 40 stitches on the needle. Shade number three would start at row 41 and there would be only 20 stitches on the needle. The result is that there are three bands of color, diminishing in length.
If you want to use more shades, just divide the number of stitches by the number of shades used. For five shades, for example, there would be 12 rows in each shade.
The effect of such a rug design is quite different from the one made of solid segments, where each color or shade continues to the center. In this case the center would in one color, which would be the color of the first 20 rows of each segment. The second color would only start at one-third from the center and the last color would start at two-thirds from the center. Consequently, to get a dark-toned rug, start with the darkest color. The center would automatically be the darkest shade. The outside of the rug would display all three shades equally, but the lighter color would be only a small triangular segment. To get the opposite effect, start with the lightest color.
After the last segment has been completed, cast off all stitches and sew together the first and the last segment, so that the circle is closed and the rug lies flat. Thread in all the ends at the back of the rug. Do this along the rows, threading from the outside towards the center. This will result in a uniform edge and will make it barely visible, even at the back.
Wash the rug (by hand preferably); roll in a towel to extract moisture, or spin dry. Then lie flat to dry on a special drying rack or on a heavy towel. You may want to shape the rug if necessary.