I'm pretty positive Diamond shapes signs are warning signs.
you have two diamonds and a cross
Wheel of Fortune
no
Used for recreational area guide signs.
Diamonds can be cut into almost any shape.
Do you mean diamonds as in diamond rings, or as in a pack of cards? If the crystal version, then you can't do anything with them other than by grinding bits off to change the shape.
Three diamonds arranged in a line can form the shape of a triangle.
Octahedron
a cube
no
Retro diamonds are basically fake diamonds.
As found in their natural state, any