plant assigns 
each element in list set seed.
This will replace and ending seeds values already set for the 
objects in the list.The graft function replicates an object with independent substreams.
The result from graft should be used with harvest.
plant(.list, seeds = gather(length(.list), ...), ...)
graft(x, n, seeds = sprout(x, n))farm, gather,
  harvest, sprout