Interior layout — The use of space is optimized by central common areas surrounded by cells. A prison or jail built “in the round” simply functions more efficiently as an incarcerating facility. Sight lines are clear so there’s a better view of all that goes on. Sprayed concrete is much tougher than conventional concrete. The amount of heating and cooling is vastly reduced. But the speed of construction is substantially increased, so that time from plan to finish is really quite rapid.