Could a well-coordinated phalanx of robots dynamically assemble a lens that would be large enough, and focus on a tight enough point, to weaponise direct sunlight against armoured mechs?
lots of searches about setting fire to things with magnifying glasses, equations for the energy density increase, and then 'energy density to ignite materials', which hasn't been terribly fruitful. Time to ask the ultimate search engine: father who used to be a science teacher
