The Temportal is a time travel device. It
consists of a large stone ring with runes around its perimeter. The rune
at the top of the ring represents the present (1996). Runes to the left
represent different eras in the past, and to the right represent the future.
There is a indicator that can be moved around the outside to specify an
era. The center of the ring is a portal to a different time. When you select
an era, the center clouds over and becomes opaque. You may pass through
the ring into the era selected. On the other side of the ring the era indicator
is set for the era that you left, thus passing back through the portal sends
you back whence you came.
See a VRML model of the Temportal