-- local coordinates!
local tArgs = { ... }
local x = tArgs[1]
local y = tArgs[2]
local z = tArgs[3]
local fuel = 16
local up = true
local fw = false

local function digUp()
    for i = 2, z do
        while not turtle.up() do
            turtle.digUp()
        end
    end
end

local function digDown()
    for i = 2, z do
        while not turtle.down() do
            turtle.digDown()
        end
    end
end

local function digVertical()
    if up then
        digUp()
    else
        digDown()
    end
    up = not up
end

local function digFw()
    while not turtle.forward() do
        turtle.dig()
    end
end

local function turn()
    if fw then
        turtle.turnRight()
    else
        turtle.turnLeft()
    end
end

local function refuel()
    if turtle.getFuelLevel() <= 4 * z then
        if not turtle.refuel() then
            print("No fuel!")
        end
    end
end

for i = 1, x do
    digFw()
    turn()
    fw = not fw
    for j = 2, y do
        digVertical()
        digFw()
        refuel()
    end
    digVertical()
    turn()
end