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==Explanation==
 
==Explanation==
{{w|Nerd}}s have a way of getting distracted easily and focusing on one thing and ignoring the rest, when they feel their specific skills are challenged by an interesting problem. [[Black Hat]] has decided to make this into a disturbing game of getting nerds, in this case a physicist, to stop in the middle of a street and get crushed by traffic by showing them an interesting problem to solve. (This may be based on a real event—see the [[#Trivia|trivia]] section).  
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{{w|Nerd}}s have a way of getting distracted easily and focusing on one thing and ignoring the rest, when they feel their specific skills are challenged by an interesting problem. [[Black Hat]] has decided to make this into a disturbing game of getting nerds, in this case a physicist, to stop in the middle of a street and get crushed by traffic by showing them an interesting problem to solve. (This may be based on a real event - see the [[#Trivia|trivia]] section).  
  
 
The problem Black Hat shows is an electronics engineering thought experiment to find the resistance between two points. In normal wiring, a one-ohm resistor would result in one ohm of resistance. Two resistors connected in a series, where electricity has to go through each, has two ohms of resistance. Two one-ohm [https://www.allaboutcircuits.com/technical-articles/resistors-in-parallel-circuit-analysis-with-parallel-resistance/ resistors in parallel] give the circuit only half an ohm since you have a conductivity (inverse resistance) that is the sum of the conductivities of the path (1 ohm of resistance is 1/1 {{w|Siemens_(unit)#Mho|mho}}, thus over 2 paths is 2 mho or 1/2 ohms). With an infinite grid of equal resistors, you have an infinite number of paths to take, and for each path an infinite number of both series and parallel paths to consider, so much more advanced methods are needed. The exact answer to the question is (4/π − 1/2) ohms, or about [http://oeis.org/A211074 0.773]  ohms.  See [http://www.mathpages.com/home/kmath668/kmath668.htm Infinite Grid of Resistors].
 
The problem Black Hat shows is an electronics engineering thought experiment to find the resistance between two points. In normal wiring, a one-ohm resistor would result in one ohm of resistance. Two resistors connected in a series, where electricity has to go through each, has two ohms of resistance. Two one-ohm [https://www.allaboutcircuits.com/technical-articles/resistors-in-parallel-circuit-analysis-with-parallel-resistance/ resistors in parallel] give the circuit only half an ohm since you have a conductivity (inverse resistance) that is the sum of the conductivities of the path (1 ohm of resistance is 1/1 {{w|Siemens_(unit)#Mho|mho}}, thus over 2 paths is 2 mho or 1/2 ohms). With an infinite grid of equal resistors, you have an infinite number of paths to take, and for each path an infinite number of both series and parallel paths to consider, so much more advanced methods are needed. The exact answer to the question is (4/π − 1/2) ohms, or about [http://oeis.org/A211074 0.773]  ohms.  See [http://www.mathpages.com/home/kmath668/kmath668.htm Infinite Grid of Resistors].

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