I was very happy when I found it.
It is just good for the envelope plot for the ensemble means, such as Historical run, or RCP runs of the CMIP5 data sets.
Required: min, max values by time.
go fill_between poly/over/nolab/palette=gray_light/pattern=dark_up_left_to_right tsequence(low[l=1:100]) tax tsequence(high[l=1:100])
function name: fill_between
red fonts: changable to other options
blue fonts: should put variable as min (low) and mix (high) value
So, Simple 🙂 try it!!