Orientation on click part?

Hi, I made a script, if the player clicks on a part, the part's orientation will get rotated with 15° degrees. But how do I repeat it? I mean when the Orientation reaches the Vector3.new(0,0,0) again, then the player can't rotate the part anymore.

local clickdetector = script.Parent.Parent.ClickDetector
local part0 = script.Parent.Parent.Parent.Part0

clickdetector.MouseClick:Connect(function()
	if part0.Orientation == Vector3.new(0,0,0) then
		part0.Orientation = Vector3.new(0,0,-15)
	elseif part0.Orientation == Vector3.new(0,0,-15) then
		part0.Orientation = Vector3.new(0,0,-30)
	elseif part0.Orientation == Vector3.new(0,0,-30) then
		part0.Orientation = Vector3.new(0,0,-45)
	elseif part0.Orientation == Vector3.new(0,0,-45) then
		part0.Orientation = Vector3.new(0,0,-60)
	elseif part0.Orientation == Vector3.new(0,0,-60) then
		part0.Orientation = Vector3.new(0,0,-75)
	elseif part0.Orientation == Vector3.new(0,0,-75) then
		part0.Orientation = Vector3.new(0,0,-90)
	elseif part0.Orientation == Vector3.new(0,0,-90) then
		part0.Orientation = Vector3.new(0,0,-105)
	elseif part0.Orientation == Vector3.new(0,0,-105) then
		part0.Orientation = Vector3.new(0,0,-120)
	elseif part0.Orientation == Vector3.new(0,0,-120) then
		part0.Orientation = Vector3.new(0,0,-135)
	elseif part0.Orientation == Vector3.new(0,0,-135) then
		part0.Orientation = Vector3.new(0,0,-150)
	elseif part0.Orientation == Vector3.new(0,0,-150) then
		part0.Orientation = Vector3.new(0,0,-165)
	elseif part0.Orientation == Vector3.new(0,0,-165) then
		part0.Orientation = Vector3.new(0,0,180)
	elseif part0.Orientation == Vector3.new(0,0,180) then
		part0.Orientation = Vector3.new(0,0,165)
	elseif part0.Orientation == Vector3.new(0,0,165) then
		part0.Orientation = Vector3.new(0,0,150)
	elseif part0.Orientation == Vector3.new(0,0,150) then
		part0.Orientation = Vector3.new(0,0,135)
	elseif part0.Orientation == Vector3.new(0,0,135) then
		part0.Orientation = Vector3.new(0,0,120)
	elseif part0.Orientation == Vector3.new(0,0,120) then
		part0.Orientation = Vector3.new(0,0,105)
	elseif part0.Orientation == Vector3.new(0,0,105) then
		part0.Orientation = Vector3.new(0,0,90)
	elseif part0.Orientation == Vector3.new(0,0,90) then
		part0.Orientation = Vector3.new(0,0,75)
	elseif part0.Orientation == Vector3.new(0,0,75) then
		part0.Orientation = Vector3.new(0,0,60)
	elseif part0.Orientation == Vector3.new(0,0,60) then
		part0.Orientation = Vector3.new(0,0,45)
	elseif part0.Orientation == Vector3.new(0,0,45) then
		part0.Orientation = Vector3.new(0,0,30)
	elseif part0.Orientation == Vector3.new(0,0,30) then
		part0.Orientation = Vector3.new(0,0,15)
	elseif part0.Orientation == Vector3.new(0,0,15) then
		part0.Orientation = Vector3.new(0,0,0)
	end
end)