A drawing made with very simple tools, usually imageboard/bbs-embedded drawing software, characterized by thin jaggy lines.
Oekaki (お絵描き) is Japanese for "scribble" or "doodle". On the Internet, an Oekaki is a message board system that revolves around computer art created with a simple drawing program built in to the website. Such message boards were most popular in the early 2000s. Oekaki artists often post their art to other websites, such as personal pages or free gallery websites, in addition to the original board.
A specific form is known as "binary art", the use of limited colors, no color blending, no antialiasing, and not low resolution, distinguishing it both from pixel art and general digital art.
