1/28/2004
slide
19
Three Types of Surfaces
•
Convex
–
Like an egg
shell
–
Curves down
for observer at
any point on
surface
•
Concave
–
Like inside of
egg shell
–
Curves up for
observer at
any point on
surface
–
•
•
Saddle
–
Like horse saddle
–
Curves down one
way, up the other
for observer at any
point on surface