Hi
Sorry no pix . The one I remember was a FW planted was built into a wall so only the front was exposed to viewing. The two shorter angled sides were behind the wall so from the viewing side there were no sidewalls .F ish would disappear from view The apex of the angle in back was offset from the center.
The optical effect was that there were no sides and gave a great illusion of depth. because of the angled back. Service was done from the room that housed the tank. Since you're placing yours in a corner you'd have to make the back walls equal??
While this shape did give a great optical effect ,eliminated the sides and flat back, it made for a very odd shaped stand and lighting arragement lol but since in a wall not really a problem.
I thought a "diamond "was an irregular rectangle??
Whatever good luck with your project lol gary