Benchmark: timing 100 iterations of /o, qr...
        /o:  7 wallclock secs ( 6.88 usr +  0.00 sys =  6.88 CPU) @ 14.53/s (n=100)
        qr: 20 wallclock secs (18.84 usr +  0.00 sys = 18.84 CPU) @  5.31/s (n=100)