of the form vs in the form

Question

1. The structure is of the form of X.
2. The structure is in the form of X.

What is the difference in meaning and which one is grammatically correct?

I think 1 means the structure is united with the form of X and 2 means the structure is shaped in the form of X

So, as for 1, I don't think the entire shape of the structure must look in the form of X (maybe ,part of it is united with the form of X?), but as for 2, I do think the entire shape of the structure must look in the form of X.

I wonder whether my thinking is correct.

Answer 1

The structure is of the form of X.

This means that the object is partially or may be totally as X. Note that this covers both the possibilities.

E.g. The cave is of the form of a tavern.

The structure is in the form of X.

This means that the whole object or the whole structure of the object is same to same as that of X. That means it is totally inspired by the X.

E.g. The cake is in the form of a Barbie Doll.