Tree Planter

print("Spacing between sapplings?")
spacing = tonumber(read())
print("Enter grid size")
gridSize = tonumber(read())
slot = 1
direction = 0
placed = 0
switchNum = 64
function plant()
    down = true
    ups = -1
    while down == true do
        down = turtle.down()
        ups = ups+1
    end
    turtle.up()
    turtle.select(slot)
    if placed > switchNum then
        slot = slot+1
        turtle.select(slot)
        switchNum = placed+63
    end
    turtle.placeDown()
    placed = placed+1
    while ups > 1 do
        turtle.up()
        ups = ups-1
    end
end

function line()
    lineLength = gridSize
    while lineLength > 0 do
        moveX = spacing
        while moveX > 0 do
            turtle.forward()
            moveX = moveX-1
        end
        plant()
        lineLength = lineLength-1
    end
end

function level()
    desiredLines = gridSize
    while desiredLines > 0 do
        if direction == 0 then
            plant()
            line()
            moveX = spacing
            turtle.turnRight()
            while moveX > 0 do
                turtle.forward()
                moveX = moveX-1
            end
            turtle.turnRight()
            direction = 1
            desiredLines = desiredLines-1
        end

        if direction == 1 then
            plant()
            line()
            moveX = spacing
            turtle.turnLeft()
            while moveX > 0 do
                turtle.forward()
                moveX = moveX-1
            end
            turtle.turnLeft()
            direction = 0
            desiredLines = desiredLines-1
        end
    end
end


level()