How do i make them all change different color?

So basically, This is not working and i wonder why, The problem is only 1 changes colour, How do i fix this?

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wait(0.5) 

while true do 
local i = math.random(1,3) -- change these numbers for the wait time it is set at 30 seconds to a minute, right now.
wait(i * 60) 
i = math.random(1,2) -- UP to 5 events; change value if you need more events 
if i == 1 then 
local j = Instance.new("Message") 
j.Parent = game.workspace 
j.Text = "The world is being torn apart!" 
wait(3) -- this is wait for the message 
j:Remove() -- remove message 
j.Text = "XD" 
wait(3) -- this is wait for the message 
j:Remove()
game.Workspace.X.Part.BrickColor = BrickColor.new("Royal purple") --Tree 1 -- (YES WORKING)
game.Workspace.X.Part2.BrickColor = BrickColor.new("Royal purple")

game.Workspace.X.Part.BrickColor = BrickColor.new("Royal purple") game.Workspace.X.Part2.BrickColor = BrickColor.new("Royal purple")-- Tree 2 --(NOT WORKING) --- Tornado