Benchmark: timing 1000000 iterations of p1, p2, p3, p4, p5, p6, p7...
        p1: 61 wallclock secs (45.42 usr +  0.16 sys = 45.58 CPU)
        p2: 45 wallclock secs (35.92 usr +  0.11 sys = 36.03 CPU)
        p3: 127 wallclock secs (102.34 usr +  0.31 sys = 102.65 CPU)
        p4: 90 wallclock secs (71.84 usr +  0.31 sys = 72.15 CPU)
        p5: 58 wallclock secs (46.11 usr +  0.14 sys = 46.25 CPU)
        p6: 55 wallclock secs (43.51 usr +  0.15 sys = 43.66 CPU)
        p7: 85 wallclock secs (68.11 usr +  0.22 sys = 68.33 CPU)