  Effective theories are helpful tools to gain an intuitive insight into
phenomena governed by complex laws. In this work we show by means of Monte
Carlo simulations that Z(2) spin models with only spin-spin interactions
approximate rather well the critical behavior of SU(2) gauge theory at finite
temperature. These models are then used to formulate an effective description
of Polyakov loop percolation, which is shown to reproduce the thermal critical
behaviour of SU(2) gauge theory.
