First of all we must turn on the toaster, put in the bread and wait for several minutes
to bake it. To prevent burning out the bread, heater of the toaster must produce heat in
temperature interval (upper and lower temperature limits). For this purpose thermometer
measures the temperature of heater, and when the upper limit of temperature is reached
then heater must go into idle state. This state resists until heater's temperature decreases to
lower limit, and then working state is again aimed
Draw a state diagram that describe the steps of making a toast