Design: "A bridge that can deploy itself on any river, in any city, any climate, safe in any whether, handle any vehicle (even ones designed after the bridge wa

Design: "A bridge that can deploy itself on any river, in any city, any climate, safe in any whether, handle any vehicle (even ones designed after the bridge was deployed), with guaranteed time to cross (99th percentile under 5s), and regularly replace itself with newer version (while people are using it). It also has to be nuclear-attack resistant, and prevent 99% suicides. All built from readily available, standard components. On $100k budget, in 3 months."