To perceive is to see and understand on something, and to interpret is to express idea.
The drawings that I drew in class are drawing self-portrait and drawing from memory. I prefer memory drawing since I can change some details that I don’t remember.
I didn’t used ‘symbol system’ because I draw people a lot so the see the shape of the face as it is.
For me, it’s easier to draw from memory because I don’t have to stuck with the realistic details, but I can imagine the part that I don’t remember.