Enclose rear and side yards. Open chain-link or ornamental metal fencing is recommended unless there is a need for privacy or noise reduction. Chain-link fencing should have its bottom edge secured with a tension wire or galvanized pipe, or should be seated in concrete to prevent easy lifting. Solid fences or walls are not recommended because they are easier to climb, provide hiding places for intruders, and are subject to graffiti. Sharp pointed fencing, i.e., fencing with spikes or a barbed- or concertina-wire topping, is not permitted in residential areas. Mount gate latches with carriage bolts and make sure that the nuts are welded on, or the bolt threads are stripped to prevent nut removal.