Toàn bộ nét vẽ trên hình là cây bút chì
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http://media.gox.vn/edu/image/e-tap-...b6f6f0_tt3.jpg
http://3.bp.blogspot.com/-nxxDbFQoWW...hien+tranh.jpg
http://a8.vietbao.vn/images/vn888/Du...ruyenthan2.jpg
http://images.vietnamnet.vn/dataimag...ando_Bloom.jpg
http://www.elqut.cn/upload_files/art...1279534400.jpg
