geometrical model of an ancient structure

Hi everyone! I am new here and I hope this is the right section for my question.
I am a student and I have some doubts about the geometrical model of an ancient greek structure. So I need some advices about my drawing that I attached here, please!
The structure is a portion of a two storey colonnade made of limestone. The feature of the structure is the segmented beam, where the blocks mutually supporting each other over inclined surfaces. The columns have been constructed by stone drums places on top of each other without connecting material between them.
I would know if I drow the correct geometrical model of this structure.
Thank you in advance.