Here’s a little resistor puzzle to keep your mind sharp over the holidays. What is the resistance of this infinite resistor network?

This can be solved numerically (and very accurately) but for this puzzle that’s considered cheating. Find the closed-form solution. And another challenge:  Write a clear, concise, explanation of how you solved it, including the math and I will publish it next week. The best answer to arrive before 00:00 GMT, January 1, “wins.” No TI peeps allowed.

Need more mental stimulation?…  Check out an earlier topic you missed:  Table of Contents for all The Signal blogs.