The secret items also include ( light switches to make it easier to see , water fountains and broken hydrants provide some health points ) or simply provide a touch of diversion and strippers who Duke tells jokes to and sometimes they open up their clothes . These locations are also filled with objects with which the player can interact , that either benefit the player in some form ( light switches make it easier to see , while water fountains and broken hydrants provide some health points ) or simply provide diversion ( tipping strippers provokes a quote from Duke and a provocative reveal from the dancer ) .