You can also do this:
local C = 1
local Colors = {
Color3.fromRGB(255,0,0),
Color3.fromRGB(0,255,0),
Color3.fromRGB(0,0,255)
}
local TweenService = game:GetService("TweenService")
local Light =
while wait() do
local T = TweenService:Create(Light,TweenInfo.new(1),{Color = Colors[C]})
T:Play()
T.Completed:Wait()
if C == #Colors then C = 1
else C += 1
end
end