stack items on top of each other

local Players = game.Players

Players.PlayerAdded:Connect(function(player)
	local playerData = workspace.PlayerData:Clone()
	playerData.Parent = player
	playerData.Name = "Data"

	player.CharacterAdded:Connect(function(char)
		-- reset every time the character respawns
		for _, stackValue in playerData.Stacks:GetChildren() do
			stackValue.Value = 0
		end

		local itemStack = Instance.new("Folder")
		itemStack.Name = "ItemStack"
		itemStack.Parent = char
	end)
end)



for _, vm in workspace.VendingMachines:GetChildren() do
	local proxPrompt = vm:FindFirstChild("ProximityPrompt", true):: ProximityPrompt

	proxPrompt.Triggered:Connect(function(player)

		local character = player.Character
		local itemStack: Folder = character.ItemStack
		local itemStackArray: {Model} = character.ItemStack:GetChildren()
		local stackSize = #itemStackArray
		local item = vm:FindFirstChildOfClass("Model")
		local newItem = item:Clone()

		local itemValue = player.Data.Stacks[newItem.Name]

		if itemValue.Value >= 5 then
			return
		end


		local finalPivot

		if stackSize >= 1 then
			local previousItem = itemStackArray[stackSize] :: Model
			local prevItemPivot = previousItem:GetPivot()
			local prevItemSizeY = previousItem:GetExtentsSize().Y
			local newItemSizeY = newItem:GetExtentsSize().Y
			finalPivot = prevItemPivot * CFrame.new(0, (prevItemSizeY + newItemSizeY) / 2, 0)
		else
			local offsetInfrontOfPlayer = character:GetPivot().LookVector * 2.5
			finalPivot = CFrame.new(character:GetPivot().Position + offsetInfrontOfPlayer)
		end

		newItem:PivotTo(finalPivot)


		local wc = Instance.new("WeldConstraint")
		wc.Part0 = newItem.PrimaryPart
		wc.Part1 = character.UpperTorso
		wc.Parent = newItem.PrimaryPart


		itemValue.Value += 1
		newItem.Parent = itemStack

	end)
end