|context> => |context: Fibonacci method 3 with active load>

fib |0> => |0>
fib |1> => |1>

n-1 |*> #=> arithmetic(|_self>,|->,|1>)
n-2 |*> #=> arithmetic(|_self>,|->,|2>)
fib |*> #=> arithmetic( fib n-1 |_self>, |+>, fib n-2 |_self>)
fib-ratio |*> #=> arithmetic( fib |_self> , |/>, fib n-1 |_self> )

fib |10> => fib |10>
fib |11> => fib |11>

fib |20> => fib |20>
fib |21> => fib |21>

fib |30> => fib |30>
fib |31> => fib |31>

fib |40> => fib |40>
fib |41> => fib |41>

fib |50> => fib |50>
fib |51> => fib |51>

-- of course, this means it is trival to DoS someone using untrusted sw files!
-- eg:
-- fib |1000> => fib |1000>