I would pick any "hard problem" and I will try to come up with a reasonable implementation. A short list of "hard" problem: * writing a compiler * a key valu

I would pick any "hard problem" and I will try to come up with a reasonable implementation. A short list of "hard" problem: * writing a compiler * a key value distribuite storage system * embedded databases * a constrain solver * circuit simulator * render engine You can note a couple of things, usually "hard" problem require a lot of theory, they are hard because we don't have the right abstraction, they are not really related to each other... Anyhow "seniorities" is not really about the capability of solve hard problem, it is more about to empower your team to solve such problem, together.