gravel filler

turtleCursor = 1

turtle.forward()

while not turtle.detectDown() do
 turtle.select(turtleCursor)
 while turtle.placeDown() do
  if turtle.getItemCount(turtleCursor) < 1 and turtleCursor < 16 then
   turtleCursor = turtleCursor + 1
   turtle.select(turtleCursor)
  elseif turtleCursor > 16 then
   return
  end
 end
 turtle.forward()
end