[21] a b
[22] b c a
[Figure 23]
[Figure 24]
[Figure 25]
[Figure 26]
[Figure 27]
[Figure 28]
[Figure 29]
[Figure 30]
[Figure 31]
[32] a a a a a
[33] b b b
[34] c c c
[35] a b a b a
[36] a b a
[37] b b a a
[38] b b b b@a a
[39] a@c b@d b@c@f
[40] a@b d@b c@c@f
[41] a@b@c
[42] c c@d d@b@a@c@f@f@f@f@e@f@f@f@f@e
[43] p@k@i@a@b@c@d@e@f@g@h
[44] a a@b@c
[45] c@d@b a@e f
[Figure 46]
[47] a b
[48] a b
[49] d a d b d c d
[50] f d f b b c c c c a