Newspaper Easter egg
From Halopedia, the Halo wiki
The newspaper Easter egg is an Easter egg found on the Halo: Reach level New Alexandria.
The Easter egg is composed of a group of newspapers arranged to form a smiley-face. It can be found on the roof of SinoViet Center, above the green SinoViet symbol on the side of the building.
To get to it, at the beginning of the level go into your falcon and go to the roof of the building in front of you (with the yellow-green sign) and go to the roof. The Easter egg is up there.