Purpose: to practice observational drawing skills, paying close attention to light, perspective, value, and proportion. To practice drawing from life; To create a good range of values to help make the objects appear 3D; To practice accurate perspective and placement. To practice angles and ellipses; To pay attention to detail/texture; To practice mark-making techniques: such as hatching, cross-hatching, curved or diagonal lines, and variation in the quality of the line.