Dungeon Dressing - Barriers to Entry

My dungeon corridors are really wide.  At 2.5 inches from wall to wall, that equates to 12.5 feet using the scale in common use today.  What to do when you want to force characters to march single file?  

Making separate tiles for bottlenecks doesn't appeal, so instead I went with a more flexible approach, rubble.  These two tiles of rubble serve multiple purposes.  They can create chokepoints that narrow a hallway.  They can represent collapsed tunnels that block all movement.  They can even represent low piles which slow movement but do not block missile fire.  Is there anything they can't do?

Simple basswood and real world rocks.

Of course there is.  They make terrible locking gates.  For that you need locking gates.  I've got two sets complete with keyholes.  The light makes this one look gray, but they do have a more silver sheen in person.  Not a huge fan of the angled crossbraces, but they keep it sturdy - an important factor in terrain that is likely to get tossed into a box.