Not mean to be silly, but left is the same verb as leave(but leave is irregular verb, they're just naughty if you don't have English as first language).
Technically, the curtain is on the right 
Seriously though, that's very good drapery coloring.
I am loving the texture on those curtains. Drawing fabric is hard on it's own, but PIXELING IT, now that's impressive.
Somehow I wasn't able to post my comment.
Thank you for pointing it out.Actually, I know left is the same verb as leave.I wanted to say "It is left behind" or so... (but it might make no sense.)
My mother toungue isn't English. Sometimes I can't use words correctly.English is difficult for me.:(
Do I make a rude reply ?? Even if the answer is yes,I'm not mean to do so.(I have to learn many many things about English,now I learning.Your comment really helps me.)
Sorry for my poor English,and thank you very much!(arigatougozaimasu!)m(_ _)m