CO multiples of four plus 2 in first colour
Row 1: K1, [K1, P1, K1 into next stitch, P 3 tog] to last stitch, K1, all in first colour
Row 2: Purl in first colour
Row 3: K1, [P 3 tog, K1P1K1 into next stitch] to last stitch, K1, all in second colour
Row 4: Purl in second colour
Repeat rows 1 - 4 in these two colours or add other colours as desired.
The main idea is to start any new colour on Rows 1 or 3. The purl rows
[2 and 4] are done with the front of the work
facing.