[QUOTE=Benh;311540]
I think the corner piece you had was perfect, it just needed the top marker to be pulled across slightly. Here's a very crude drawing.
Attachment 10300
Thats how it supposed to be as in the second sketch, as I said earlier the problem is if one of the two connecting pipes get hit it either stretches the corner flat or does what it did. Just needs putting back right when it is hit.