Today's jail design involves either direct or indirect monitoring. Rather than isolating convicts in rows of cells, the facility is divided into "pods" that are crowded around a central monitoring station. The idea is to give prisoners the impression that everyone else is being watched all the time. Each cell in a prison has a window and a door. The window allows light into the cell during daytime hours while the door provides access to the yard or hall. Prisoners wear identifying tags attached to their clothes. These tags can be read by security cameras located throughout the building. Jails also contain exercise yards similar to those found in prisons. The only difference is that inmates in jails can be held in segregation (separated from the general population) for a period of time without becoming physically exhausted like those who work in the prison factory line would be. This is because they are not working; they are awaiting trial or sentencing proceedings. Exercise programs vary depending on what type of facility you are in. For example, if you are in a state prison, you will likely be required to participate in some sort of physical activity program for maintenance of your health. This may include spending time in a gym setting using weight machines or just walking in a large fenced area of the campus.