The overhead monitors were stacked four rows high , twice as high as the existing trading pits , in order to maximize the use of the narrow area .
These were removed later as a result of seismic concerns and replaced with countertop flat screens .
The overhead monitors were stacked four rows high , twice as high as the existing trading pits , in order to maximize the use of the narrow area , although these were removed later as a result of seismic concerns and replaced with countertop flat screens .