36 lines describing a truncated cone
plumb bobs, string and fixings
The seemingly parallel lines that are created by a circle of suspended plumb bobs actually form part of a cone in both appearance and reality.
Visual perspective means that the vertical lines will always appear to be converging to form a virtual cone finishing at a vanishing point, which is particularly apparent when looking up at the installation from below. However, the plumb lines are also converging physically as they are drawn by gravity to the central core of the earth deep below.
These two cones travel in opposite directions, one visual cone ascending upwards that is not real and second real cone descending downwards that cannot be perceived.