It is the hardest thing to draw something transparent! This is an antique cut glass parfum bottle that I had. I used pencil, thinking that it would be easier to get that see-through effect...I don't think that it was too successful. I did love drawing the shape, however. I find that nature is very forgiving, with no real hard edges and exacting measurements. Graphic items are much harder, and force you to look harder, double check everything, and measure! I will continue to try to figure out perspective. And I have learned that the mind plays tricks on you...you only THINK you know what you are really seeing!