Sequencing is an internal order method used for lean manufacturing and just in time manufacturing.  Sequencing is predominately used when  different models with different variants are being produced on the production line at the same time.   Sequencing is a way to provide the correct variant at the correct time at the point of application for the particular model being produced. 

Let's take an example.  A production line is producing three models of refrigerators each having different handle styles.   Handles would be a commodity to be sequenced.   A broadcast signal would be sent to the sequencing center to supply each handle at a certain time to the assembly line.  In the below example, each colored widget represents a different handle style.