Method 6: 14 wallclock secs (14.08 usr +  0.02 sys = 14.10 CPU)
Method 7: 14 wallclock secs (14.14 usr +  0.01 sys = 14.15 CPU)
Method 8: 15 wallclock secs (14.12 usr +  0.01 sys = 14.13 CPU)