how can I make a lamp?

hi, I am working on a project in OpenGL, I drawn a 3D house with different rooms and I have to put lamps in it.
I placed some spheres on the ceiling to represet the lamps.
now my problem is how to make a light cone which start from the lamp and reaches the floor.

I have 8 lamp in the house ( I know that 8 is the max limit for lights in OpenGL)
how can I make this 8 little lights in the map?