About the slight difference in stone size & shape: this can actually be seen as making them more beautiful from the perspective of East-Asian (Zen Buddhist) aesthetics.
Most well-known is probably wabi-sabi. Contrary to classical Greek aesthetics, in Zen Buddhism the beauty is rather in the imperfection of things, and remaining close to nature. It’s the feeling of melancholy you get when looking at stones of slightly different size that is considered more beautiful than the cold rigidity of perfectly sized machine-fabricated stones.