Video narration
How can a painting look like you could reach out and touch it? Think about a toy building block. Drawn as a flat shape, it shows one surface. It feels like a picture on paper because paper has no part going backward. A real block has three directions. Its width goes across, its height goes up, and its depth goes from front toward back. Together, these three directions make 3D-three dimensions. Now imagine painting that block. A darker side, a lighter front, and a top edge give your eyes clues. Even though the paper stays flat, shading helps you imagine the object sticking out. If the paint is raised, it really has depth. The picture stops being only a flat surface when depth is added. A painting looks 3D when depth gives it a front, side, and back.