Office Open XML document parts shall be arranged contiguously in a package as defined by simple ordering.

Parts within an Office Open XML package shall not be interleaved. All parts shall be stored as complete ZIP items, and the interleaving functionality defined in Part 2 of this Standard shall not be used.
Note: : Part 2 of this Standard specifies a method for interleaving parts, which is a very useful capability for stream processing. In order to simplify initial implementations of the Standard, interleaving is not used in this current version of the Office Open XML formats but it may be used in further versions of the standard or by other formats that leverage OPC.