article_snippet: Great artworks sometimes come in an unexpected form.
article_snippet: Then Mr Wang's goes into a trail-and-error stage of setting out the outlines and establishing the different shades of colours of the particular picture, and this could take more than 100 alterations to get right.
article_snippet: left) Effort: To set the correct outlines and colour tones of a painting sometimes takes more than 100 alterations .