How to Draw Optical Line Illusions - Spiral Doodle Pattern 9

How to draw optical line illusions. Spiral doodle pattern number 9. This is also a good exercise to do if you want to improve drawing curves. ► My Book on Amazon (USA) https://www.amazon.com/dp/1633223558 ► My Book on Amazon (UK) https://www.amazon.co.uk/dp/1633223558 Materials used: 110lb cardstock, Sharpie