| At the top of the columns a concrete-on-steel deck platform forms the oculus of the interior dome. |
| The oculus windows depicted in each of their two cells illuminate the figures with an otherworldly silvery light. |
| A large oculus brings a cylinder of light down into the main library, bathing the interior in a softly luminous glow. |
| At the centre of the dome is an oculus, a circular hole, which is the only source of light. |
| The major interior space, the Potomac rotunda, balloons under a domed ceiling with an oculus, reaching a height of 120 feet. |
| Each of the upper study areas has an oculus in the floor revealing its counterpart below. |
