A darkish liquid ejected for cover by most cephalopods, such as the octopus and squid. Ink is made up of extremely concentrated melanin. These lines might be made inside of a uniform arrangement, or put in a more random fashion based on the texture you would like to produce. https://edwinfaqgy.blogoxo.com/36824917/the-definitive-guide-to-how-to-draw-with-ink-pens