Used three threads.
Cast on 40 st. on 2 circular needles. Pattern: K3, P2. for 13 cm. Put last 4 st. from the needle you are working on and first 4 st. of next needle on piece waste yarn. Knit on until 21 cm. Bind off loosely. Pick up 12 st. on first circular needle and 12 st. on another one. Every other round decrease a st. or two. Knit in the round for about 4 cm. Bind off loosely.