I uploaded a small library [1] for generating VCD files [2], which can be viewed with waveform tools like GTKWave [3]. Though VCD is commonly associated with Verilog simulation, at Eaton we use it to visualize vehicle data in realtime: data is pulled off the CAN bus, formated to VCD, then piped into GTKWave. Most operations are in the IO monad, but if there's a better way to do it, I'm open to suggestions. I hope to add a simple VCD parser to the library soon; again suggestions welcome. -Tom [1] http://hackage.haskell.org/package/vcd [2] http://en.wikipedia.org/wiki/Value_change_dump [3] http://en.wikipedia.org/wiki/GTKWave