These two links – inbound and outbound – play a pivotal role in the mutual updating of master sheets and sub-sheets. A cell with an inbound link is called the destination cell. Destination cells, identified by a light blue arrow, are situated on the right side of the cell. A cell with the outbound link is called the source cell, which can be linked to multiple destination cells. The source cells are identified as such by a grey arrow in the bottom-right corner of the cell. An inbound linked cell derives its value from a cell in another sheet. Conversely, when a cell contains an outbound link, it will automatically update an “inbound” destination cell in another sheet. When you create an inbound link, for a cell to receive inbound (incoming) data, an outbound link is automatically created and placed in the source sheet.