decal changing script not working and inconsistent?

Here's my script:

while true do 
script.Parent.Texture = "http://www.roblox.com/asset/?id=73866498" 
wait(0)
script.Parent.Texture = "http://www.roblox.com/asset/?id=73866498" 
wait(7)
script.Parent.Texture = "http://www.roblox.com/asset/?id=1940693447" 
wait(10)

Here's my problem: The decals aren't changing consistently and the script seems like it isn't even working. If there is an alternative I'd greatly appreciate it!

Ugh. I don't know if I'm doing this right, some wait() times work and other times I feel its just randomly spewing out the decals. Here's my updated script, which is located inside the part inside a decal:

while true do --Loop
script.Parent.Texture = "rbxassetid://73866498"
wait(10)
script.Parent.Texture = "rbxassetid://72070188"
wait(7)
script.Parent.Texture = "rbxassetid://21446331"
wait(7)
script.Parent.Texture = "rbxassetid://72070188"
wait(1)
script.Parent.Texture = "rbxassetid://72070188"
wait(10)
script.Parent.Texture = "rbxassetid://72070188"
wait(10)
script.Parent.Texture = "rbxassetid://72070188"
wait(10)
script.Parent.Texture = "rbxassetid://72070188"
wait(10)
script.Parent.Texture = "rbxassetid://72070188"
end