Click the thumbnails to enlarge.

Euclidean distance in the plane (Figure 2.1.1)

Causchy inequality for the plane (Figures 2.1.2, 2.1.3 and one extra figure, exibiting the case when the points A, B, and C are colinear)

City-street/Taxi-cab metric (Figure 2.1.6)

Open and closed sets (Figures 2.1.7 and 2.1.8)

Post office metric (Figure 2.1.9)

Exercise 11 (Figure 2.1.10)