| time | name        | event    |
|----: | :-----------| :--------|
|    1 | stacker     | put red  |
|    1 | red-picker  | got red  |
|    2 | stacker     | put blue |
|    2 | blue-picker | got blue |
|    3 | stacker     | put red  |
|    3 | red-picker  | got red  |
|    4 | stacker     | put blue |
|    4 | blue-picker | got blue |
|    5 | stacker     | put red  |
|    5 | red-picker  | got red  |
