Can you angle display mortars

[lostpup]

So being new to the display side I'm wondering if 3's,4's,or 5's can be angled safely. I have not seen any videos that I can see a set up with angled display shells. I've seen some bigger shows where the trajectory angles suggest it can be done. But are the buried or can you safely build a rack the will take the pressure and not blow a plug or rack apart.

I will be shooting several 3s and 5s for my personal show next year and hoping for some ideas to safely fan or cover more sky.

[tmwjr]

They sure can be. The ones in the back are fanned in the picture below. They are 3s and 4s. I use just a sideboard (cut up deck boards) on each side and sometimes an upper board too.
I'm not sure of the angles...no more than off 10 degrees
5315

[tmwjr]

Also, dave's video from last year at fire and thunder at the hollow has a nice setup section with angled racks.

https://youtu.be/Na38I7fMfVs

[lostpup]

Thank you guys, keep them coming if you have other videos or pictures.

[lostpup]

Also, dave's video from last year at fire and thunder at the hollow has a nice setup section with angled racks.

https://youtu.be/Na38I7fMfVs

So I revisited the video and I have seen angles like this just wasn't coming to mind.
Is there a book or anywhere to find a standard on racks and angles. 10? sounds reasonable. I'd like to find something to keep around for reference.