R1: 2 ch, then in the 2nd st of hook: 2 sc in one st.
R2: turn, 1 ch, 1 sc, 2 sc in next st.
R3: turn, 1 ch, 2 sc, 2 sc in next st.
R4: turn, 1 ch, 3 sc, 2 sc in next st.
R5: turn, 1 ch, 4 sc, 2 sc in next st.
R6: turn, 1 ch, 5 sc, 2 sc in next st.
R7: turn, 1 ch, 6 sc, 2 sc in next st.
R8: turn, 1 ch, 7 sc, 2 sc in next st.
R9: turn, 1 ch, 8 sc, 2 sc in next st.
R10-12: turn, 1 ch, 10 sc, 1 ch.
Finally, make sc a round.