I agree with Tom.

The grammar in this is poor. The sentence you are talking about isn't even written as a complete thought. It's incorrect. The author means "such as", not "and so, with". This is what the author means to say: "He must, for example, perceive an egg as a simple single solid shape, quite apart from its significance as food, or from the literary idea that it will become a bird. With solids such as a shell, a nut, a plum, a pear, a tadpole, a mushroom, a mountain peak, a kidney, a carrot, a tree-trunk, a bird, a bud, a lark, a ladybird, a bulrush, a bone, he can go on to appreciate more complex forms or combinations of several forms." Is this more clear? This is a strange passage. As a native English speaker with a university degree, it's difficult for me to understand. If you can't fully understand it, don't feel bad.

Hmmmm. "So" is a conjunction and "with" is a preposition, but the sentence is a fragment (there is no verb or complete thought.) I don't understand what the writer is trying to say either.