Design efficiency for beams How can we achieve higher strength-to-weight ratios in beam design? E.g., how can we modify conventional beam cross-section shapes to create cross-sections from the same material that are much lighter through efficient material placement? In providing your response, refer to the cross-section shapes and material placement observed in the different beams addressed throughout this subject: RC, prestressed, steel, composite, and timber. Expectation: 150-200 words.