toys/mathematics/number-theory/phi-and-pi/pi2.rb

def divide(int)
    return 4.0 / (int * (int + 1) * (int + 2))
end

answer = 3
c = 2
i = 1

while c < 100000 do
    if (i % 2 == 0) then
        puts (answer = answer - divide(c))
        c += 2
    else
        puts (answer = answer + divide(c))
        c += 2
    end
    i += 1
end