How many chiral centers in Steviol?

I count 6. Look for carbons that have four different things attached to them. They may not differ at first, but do differ as you get farther away. This is especially true in rings where there may be two (or more) CH2's attached to a carbon, but when you continue on out, they differ. For example, one CH2 may have another CH2 while the other has a CH. Even though the CH2's are not different, the two groups are still different because they differ further out.