Create a clear educational illustration of the human heart and blood circulation on a warm-white teaching board. Place a central cutaway heart showing four distinct chambers, major vessels and simplified valves, with the lungs arranged on both sides and a simplified body circulation loop extending below. Use blue pathways and directional arrows for deoxygenated blood entering the right heart and traveling to the lungs, then red pathways and arrows for oxygenated blood returning to the left heart and circulating through the body. Compose a clean 4:3 landscape diagram with polished vector clarity and subtle dimensional shading. Keep the anatomy informative and non-graphic. Use arrows only, with no labels, no letters, no numbers, no gore, no random vessels, no incorrect connections, no logo, no watermark.