Windows logo
From Halopedia, the Halo wiki
The Windows Logo Easter Egg is an Easter Egg in Halo 3. To see it is simple. On The Pit, go into the sword room and locate a phone hanging on the wall, bright yellow with a red error message on it stating that it is out of service. Melee it and it will break, over on the back of it, there is a small Windows Logo.
