+--------+----------------------------------+
| bitmap | 00000000000000010000001000000000 |
+--------+----------------------------------+
|        | +-+-+                            |
| array  | | | |                            |
|        | +++++                            |
+--------+--+-+-----------------------------+
            | |
            | +------------+
            |              |
            v              v
       /----------\  +--------+----------------------------------+
       | bar → 17 |  | bitmap | 00000000000000100000000000000010 |
       \----------/  +--------+----------------------------------+
                     |        | +-+-+                            |
                     | array  | | | |                            |
                     |        | +++++                            |
                     +--------+--+-+-----------------------------+
                                 | |
                                 | +------------+
                                 |              |
                                 v              v
                            /----------\  /----------\
                            | baz → 66 |  | foo → 42 |
                            \----------/  \----------/