-- Make a tunnel
function MiningTurtle.tunnel( length, height, width )

    width  = width  or 1
    height = height or 2

    -- Length loop

    for i = 1,length do

        MiningTurtle.saveForward()

        if i % 2 == 0 then
            -- even

            turtle.turnLeft()

            for x = 0,width do

                for y = 0,height do

                    if x % 2 == 0 then
                        MiningTurtle.saveUp()
                    else
                        MiningTurtle.saveDown()
                    end

                end

                if x < width then
                    MiningTurtle.saveForward()
                end
            end

            turtle.turnRight()

        else
            -- odd

            turtle.turnRight()

            for x = 0,width do

                for y = 0,height do

                    if x % 2 == 0 then
                        MiningTurtle.saveUp()
                    else
                        MiningTurtle.saveDown()
                    end

                end

                if x < width then
                    MiningTurtle.saveForward()
                end
            end

            turtle.turnLeft()

        end

    end

end