The Monoliths are some of Blade II Monolith Yves' earliest works.
They are made of concrete and some form of gas light source; typically, neon or fluorescents.
When the light source is turned on, the light escapes through cracks in the concrete.
One particularly interesting Monolith features depictions of Yves' face.
Some depictions were drawn by Yves as self-portraits; others are Yves re-interpretations of other artists' drawings of him.
He says that they are "...viewed by the eyes of someone else and redigested".