Cyclopropane is an interesting hydrocarbon. Instead of having
three carbons in a row, the three carbons form a ring, as
shown in this perspective drawing (see Figure 2.18 for a prior
example of this kind of drawing):
Cyclopropane was at one time used as an anesthetic, but its
use was discontinued, in part because it is highly flammable.
(b) The three carbon atoms
are necessarily in a plane. What do the different wedges
mean?