But by the same token, if we assume that GP is more than a simpleton (in the principle of charity) we must say that they would also consider art (always created by human intention) to be "imaginary lines", but I doubt they would deny paintings can have meaning. Words (usually though not always naturally evolved), by the same token, are just scrawls, but they have meaning despite being "made up" in the same way. GP knows they have meaning because he/she is using them in such a way. I read the idea that the lines are imaginary to mean that they don't have to be that way.