Time

-1-----------------2-----------------3------------->

Events

Item 1 Item 2 Item 1
Location A Location A Location B

| Time | Location A   | Location B |
|------|--------------|------------|
|    1 | item 1       |            |
|    2 | item 1 and 2 |            |
|    3 | item 2       | item 1     |



**API**

onEvent(itemId, locationId)
inventory(locationId) --> list(itemId)