 genus and the k species are s_1 through s_k,
or g is the whole pie and the slices are the s_j.

o-------------------------------------------------o
| ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` ` ` `s_1` `s_k` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` ` ` ` o ` ` o ` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` g ` ` | ` ` | ` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` o-----o-...-o ` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` `\` ` ` ` `/` ` ` ` ` ` ` ` ` ` |
| ` ` ` ` ` ` ` ` ` \ ` ` ` / ` ` ` ` ` ` ` ` ` ` |