(D)-17 . © Nikos Drelas 1 1-b 1-s2 2-b 2-s3 3-b 3-s4 4-b 4-s5 5-b 5-s6 6-b 6-s7 7-b 7-s8 8-b 8-s9 9-b 9-s 1 1-b 1-s2 2-b 2-s3 3-b 3-s