What is the nature of dendrothermal energy?

What is the most energy efficient shape found in nature? What is the most structually sound?

• I have often heard that the circle or sphere is the most energy efficient shape found in nature. Is this true, and is it the most structually sound or efficient shape?

• Answer:

  For "energy efficiency", the sphere has the lowest surface for a given volume. Therefore, a heated sphere will cool down slower than any other body made from the same material. For "structurally sound", you must first define the purpose. An empty sphere subjected to uniform external pressure is also the most sound structure, as the material will be subjected to exactly the same stress in all points; other shapes will not distribute stress with the same evenness, so there will be regions with lower stress and regions with higher stress (which will yield first, and at lower external pressure than a sphere would). Batiscaphs (used for exploring deep sea) are spheres, or have a shape close to it.