The item will wait in the last upstream residence block until the Activity block (Item library) can receive it. Residence blocks are any block that can hold an item for a non-zero amount of time. Examples include queues, activities, resource blocks, and some decision blocks. If the last residence block is a generator type block, the item will be held until a new item is created or the activity pulls the item. This is the only time that an item will be destroyed if there is downstream capacity.