platform

local w, l = ...

function selectBlock()
 c = 2
 while c <= 16 do
  turtle.select(c)
  if turtle.getItemCount() > 0 then
   return true
  end
  c = c + 1
 end
end

function goPlace()
 if turtle.getFuelLevel() <= 100 then
  turtle.select(1)
  turtle.refuel(1)
 end
 turtle.forward()
 if turtle.detectDown() == false then
  if turtle.placeDown() == false then
   selectBlock()
   turtle.placeDown()
  end
 end
end

function turn(d)
 if d == "forward" then
  turtle.turnRight()
  goPlace()
  turtle.turnRight()
  return "backward"
 end
 if d == "backward" then
  turtle.turnLeft()
  goPlace()
  turtle.turnLeft()
  return "forward"
 end
end

function start(d, w, l)
 if d == "forward" then
  turtle.turnLeft()
  turtle.turnLeft()
  while l > 0 do
   goPlace()
   l = l - 1
  end
 else
 goPlace()
 end
 turtle.turnRight()
 while w > 1 do
  goPlace()
  w = w - 1
 end
 turtle.turnRight()
end

direction = "forward"

wc = tonumber(w)
while wc > 0 do
 lc = tonumber(l)
 while lc > 0 do
  goPlace()
  lc = lc - 1
 end
 wc = wc - 1
 if wc > 0 then
  direction = turn(direction)
 end
end
start(direction, tonumber(w), tonumber(l))