Crazy realistic DRAWING: a MARBLE or glass BALL

How to draw 3D glass and transparent things using mixed media on gray paper. Crazy 3D drawing of a marble ball

I would like to share presentations that I like and that I prepared on my own. I am very pleased if you follow my vote and vote. I have a Dream , when I come to a certain level, I will focus only on it. Help this dream :).
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Video is quoted. Video taken from YouTube.