Effect not showing up on guis - user-interface

Question

I'm making an effect in my game where it scrolls through some choices and slows down to a stop on one choice.
There's 4 screens and I want each one to play the effect simultaneously, all the guis show up at the same time but the effect never plays. I've marked the part of the code that does the effect in the block of code below:
message.chooseduel = function(spins)
local lobby=workspace.Lobby
local screens=lobby.Screens
local n1,n2
for _, screen in pairs(screens:GetChildren()) do
local gui=screen.SurfaceGui
local ds=gui.DuelScreen
gui.Enabled=true
for i, v in pairs(ds.Container:GetChildren()) do
local ll
local lastpicked
local t = ds.Container:GetChildren()
local menuItems = #t -- number of menu items
local repeats = 1 -- Repeated
for R = 65 + spins, 1, -1 do
ll = t[repeats]
if ll:IsA("GuiObject") then
--**effect**--
local newgui = coroutine.wrap(function()
print("HI!")
ll.BackgroundColor3=Color3.fromRGB(130, 125, 56)
wait( R^-.7*.7 ) --
ll.BackgroundColor3=ll.BorderColor3
repeats = repeats % menuItems + 1
end)
newgui()
--**effect**--
end
end
ll = t[repeats]
ll.BackgroundColor3=Color3.fromRGB(230, 225, 156)
n1=string.sub(ll.n1.Image,64)
n2=string.sub(ll.n2.Image,64)
print("Returning:",n1,n2)
end
end
wait(2)
return {n1,n2}
end

Answer 1

Hope this helps:
message.chooseduel = function(spins)
spins = math.ceil(spins) -- just making sure.
local lobby=workspace.Lobby
local screens=lobby.Screens
local n1,n2
for _, screen in pairs(screens:GetChildren()) do
local gui=screen.SurfaceGui
local ds=gui.DuelScreen
gui.Enabled=true
spawn(function() -- I think this is where the coroutine / async function should start
local ll
local lastpicked -- Variable not used
local t = ds.Container:GetChildren()
local numMenuItems = #t -- number of menu items
local current = 1 -- Repeated
print("HI!")
for R = 65 + spins, 1, -1 do
ll = t[current]
if ll:IsA("GuiObject") then
ll.BackgroundColor3=Color3.fromRGB(130, 125, 56)
wait( R^-.7*.7 ) --
ll.BackgroundColor3=ll.BorderColor3
current = current % numMenuItems + 1
end
end
print("BYE!")
ll = t[current]
ll.BackgroundColor3=Color3.fromRGB(230, 225, 156)
n1=string.sub(ll.n1.Image,64) -- um... Interesting. wait what?
n2=string.sub(ll.n2.Image,64)
print("Returning:",n1,n2)
end)
end
wait(2)
return {n1,n2}
end
I'm not sure I totally get what you are doing here or how you have things set up, but in general you should try to move coroutines / spawned functions to the outsides of loops.