sanity test for correctness
Benchmark: timing 50 iterations of One, Three, Two...
   One: 29 wallclock secs (28.41 usr +  0.00 sys = 28.41 CPU) @  1.76/s (n=50)
 Three: 10 wallclock secs (10.00 usr +  0.00 sys = 10.00 CPU) @  5.00/s (n=50)
   Two: 10 wallclock secs (10.03 usr +  0.00 sys = 10.03 CPU) @  4.98/s (n=50)