3 colours of Double Knitting yarn, approximated 30-50g of each.
5mm circular needle.
Ring 1: Holding yarn A double, cast on 100st, join. Knit 10 rows. Cast off. Weave in ends.
Ring 2: As Ring 1 using a different colour of yarn (yarn B).
Ring 3: Holding yarn C double, cast on 100st. Do not join.
Arrange Ring 1 and Ring 2 as shown.
Weave the circular needle under Ring 1, over Ring 2, under Ring 1, and over Ring 2. Join. Knit 10 rows. As you knit move Rings 1 and 2 out of the way. Cast off, and weave in the ends.