The image is a blackboard with a detailed blueprint or technical drawing on it. The drawing is in white chalk and shows various lines and shapes that represent different components of a machine or machinery. The lines are arranged in a grid-like pattern and are labeled with Chinese characters. The background of the blackboard is dark, making the drawing stand out. The text on the drawing is written in a neat and legible font. The overall style of the drawing appears to be old and worn, suggesting that it has been used for a long time.