toCoords ::
  Coord   {- ^ origin -} ->
  [Vec]   {- ^ steps  -} ->
  [Coord] {- ^ path   -}
toCoords = scanl step
toCoords ::
  Coord   {- ^ origin -} ->
  [Vec]   {- ^ steps  -} ->
  [Coord]
toCoords = scanl step
toCoords = scanl step