  We argue that a nonthermally looking spectrum of a gamma-ray burst (GRB) can
be formed as a superposition of a set of thermal blackbody spectra. This
superposition may be done by time integration which is present even in `time
resolved' GRB spectroscopy. A nonthermal spectrum can be obtained also by the
space integration which should take place unless all the emission comes from a
plane front moving exactly towards the observer. We propose a model of the
gamma-ray burst spectrum formation based on this idea. This model allows the
GRB radiation to be optically thick and to have higher values of baryon load.
Thus the latter is limited by the energy considerations only, and not by the
condition of a small optical depth.
