Benchmark: timing 100 iterations of html, join, local, manual...
      html: 46 wallclock secs (45.58 usr +  0.05 sys = 45.63 CPU) @  2.19/s (n=100)
      join: 220 wallclock secs (219.65 usr +  0.07 sys = 219.72 CPU) @  0.46/s (n=100)
     local: 221 wallclock secs (220.61 usr +  0.14 sys = 220.75 CPU) @  0.45/s (n=100)
    manual: 866 wallclock secs (864.92 usr +  0.26 sys = 865.18 CPU) @  0.12/s (n=100)