i would think 45 degree's horizontal and not vertical.
And have the points either face each other or away from each other.
If you did straight they could push it straight and off.
If you did it in a vertical 45, they could the same either step or lift it off.
You would have a set motion path in which the nails could come out.
But if you did 45 in a horizontal and had the tips face each other or are away from each other, its gonna be pretty darn hard to pull that thing off because there is no range of motion it can go.
End of serious mode.
Now sarcasm mode... dont board up the house, weld it with iron bars.
That way u have gaps to shoot them from, and they cant pull it off.
Don't board up your house, that's the #1 rule.
I wouldn't board up my house. I'd just go full auto on the zombie horde. :awe:
LOL
Sorry wont work, I have enough hours in L4D and CoD5 to show ya, that's a quick way to say goodbye to your life.