CC Turtle Tree Farm

function start()

    moveFw(3)

    turtle.turnRight()
    moveFw(1)

   plantRow()

    for i=2, 4 do
        if(i%2 == 0) then
            turtle.turnLeft()
            moveFw(4)
            turtle.turnLeft();
        else
            turtle.turnRight()
            moveFw(4)
            turtle.turnRight();
        end
        plantRow()
    end
end

function plantRow()
    placeTree()

    for i=1, 3 do
        moveFw(3)
        placeTree()
    end
    moveFw(1);
end

function moveFw(distance)
    if distance ~= nil then
        distance = tonumber (distance) -- make it a number
        for i = 1, distance do
            turtle.forward()
        end
    else
        print ("Did not specify distance.")
    end
end
function placeTree()
    turtle.forward()
    turtle.select(3)
    turtle.place(Sapling)
    turtle.forward()
    turtle.select(4)
    turtle.place(Torch)
end


function refuel()
    turtle.select(16)
    turtle.refuel(20)
    if (checkFuel) then
        start()
    end
end

function checkFuel()
    local fuel = turtle.getFuelLevel()

    if (fuel < 10) then
        return false
    end
    return true
end

refuel()
start()