
6.6. SHIFT METHOD 203
Figure 6.7 Definition of point µ(P
1
, P
2
) as the intersection of the line with slope +1
passing through P
1
and the line with slope −1 passing through P
2
.
w
1
= v
1
w
t - 1
w
2
w
t
= v
2
w
p
w
q
Figure 6.8 Schematic illustration of a drawing of Γ
k−1
that satisfies the contour condi-
tions, i.e., the external face is drawn as a polygon consisting of a horizontal edge and a
chain of segments with slope +1 or −1 between endpoints P (v
1
) = (−((k − 1) − 2), 0) and
P (v
2
) = ((k − 1) − 2, 0).
w
1
= v
1
w
t
= v
2
w
t - 1
w
2
w
p
w
q
v
k
Figure 6.9 Schematic illustration of the addition of vertex v
k
to drawing Γ
k−1
to obtain
drawing Γ
k
. Contour ...