What is the color of the smoke?
The smoke is gray.
     src        edge_attr  dst
0      2  to the right of   35
1      2  to the right of   39
2      2               in   14
3      3   to the left of   32
4      3   to the left of   33
..   ...              ...  ...
166   38  to the right of   18
167   39   to the left of   16
168   39  to the right of   37
169   39   to the left of    2
170   39  to the right of   15

[171 rows x 3 columns]