The Pink Spheres are a group of 3 spheres with the "Hot Pink" color hidden within the rear of the Wood R Us ceiling.
When viewed in studio, the spheres are labelled to hold the following values, with respect to the image: Playermodels, Logmodels, and Effects. This means that the spheres are there solely for holding certain game data. The spheres are likely colored pink due to the tendency of scripted parts to have such color in the game. It is currently unknown why the spheres need to exist, or why they are within the roof.
The most commonly used method of observing the spheres is by using the integrated Shift-Lock mode (found in the ROBLOX menu) while jumping up and down in the Wood R Us truss opening. Because Shift-Lock offsets the camera to the right, the player can get glimpses of the pink spheres when their camera is in the ceiling. These can also be seen during Server Initialization; they typically load into the game before the Wood R Us.