4 adjectives to describe octagon

What is an irregular octagon?

" "Well, then," she answered, "give me the little octagon beside your own:"the smallest and simplest, but to my taste the prettiest, room in the house.

Studying its ground-plan, and noting how the nave unfolds into a mighty octagon, which in its turn displays three well-proportioned apses, we are induced to think that a sublimer thought has never been expressed in stone.

He drew it from the water; it was a block of wood, in the form of an octagon, highly polished, inlaid with bits of pearl, forming grotesque figures, and thickly studded with some bright mineral, representing stars, which gave it a very handsome appearance.

4 adjectives to describe  octagon