  We investigate the structure of center projected vortices of SU(2) lattice
gauge theory at zero and finite temperature. At zero temperature we find, in
agreement with the area law behaviour of Wilson loops, that most of the
P-vortex plaquettes are parts of a single huge vortex. This vortex is an
unorientable surface and has a very irregular structure with many handles.
Small P-vortices, and short-range fluctuations of the large vortex surface, do
not contribute to the string tension. At finite temperature P-vortices exist
also in the deconfined phase. However, they form cylindric objects which extend
in time direction and consist only of space-space plaquettes.
