* "Free form" should be used as an adjective, not a noun phrase.
* "Was" requires a noun or noun phrase after it.
Here are some ways to correct the sentence:
* "The sculpture was free-form." This uses the correct adjective form.
* "The sculpture was a free-form creation." This clarifies the type of sculpture.
* "The sculpture was designed in a free-form style." This provides more context about the design.
Let me know if you'd like to explore more options!