Airflamesred:

If you look at sci-fi doors, you'll see that by creating the zig-zag you are increasing the amount and strength of the seal and/or locking mechanism. Simply butting the two doors together means that a standard door is quite weak at the join.

Available on Amazon for the Kindle E-Reader

All the Woes of a World by Jonathan Icknield aka The Bryster

And in my final hours - I would cling rather to the tattooed hand of kindness - than the unblemished hand of hate...