  This paper formally proposes a problem about the efficient utilization of the
four dimensional space-time. Given a cuboid container, a finite number of rigid
cuboid items, and the time length that each item should be continuous baked in
the container, the problem asks to arrange the starting time for each item
being placed into the container and to arrange the position and orientation for
each item at each instant during its continuous baking period such that the
total time length the container be utilized is as short as possible. Here all
side dimensions of the container and of the items are positive real numbers
arbitrarily given. Differs from the classical packing problems, the position
and orientation of each item in the container could be changed over time.
Therefore, according to above mathematical model, the four-dimensional
space-time can be utilized more truly and more fully. This paper then proves
that there exists an exact algorithm that could solve the problem by finite
operations, so we say this problem is weak computable. Based on the
understanding of this computability proof, it is expected to design effective
approximate algorithms in the near future. A piggyback work completed is a
strict proof on the weak computability over general and natural case of the
three-dimensional cuboid packing decision problem that all parameters are
positive real numbers.
