Writing Systems of the World 1, Exercise 3: drawing versus writing

A drawing of a deer shows a deer; anyone can read it in any language, and it
does not say what words to use. The Writing system article excludes drawings
and maps from writing on the narrow definition.

A symbol that is always read as the word "deer" is tied by convention to a
particular language's word, which is what makes it a unit of writing. The
article's term proto-writing covers the in-between case: ideographic and
mnemonic symbols that lack the capability to fully encode language, such as
the Inca quipu. The article notes most proto-writing systems did not become
writing systems.

(My own wording; the conclusion follows the article's definition, which is a
narrow one and not the only one scholars use.)