The program introduces a number of overlapping themes or ideas to consider. The primary task is to create a boundary and threshold between the buildable portion of the protected historic cave area. Conceptually it is a boundary between the “present day suburban condition” and the interior protected cave or “deep time” of the Pleistocene epoch (ice age). This is both a literal and conceptual boundary experience. Consider the experience of going back in time 20,000 years or so.