>One of Musk's original points was that cost of tunneling isn't linear with diameter--double the size more than quadruples the price Ignoring all the other cha

>One of Musk's original points was that cost of tunneling isn't linear with diameter--double the size more than quadruples the price Ignoring all the other challenges of scale, this would surely make sense because the area of a circle scales with the square of the diameter...