The number three strikes again. This fence has three layers. Three, however, seems to be the right number of layers for this fence. Two seems too sparse; kids can get through easily as they would be too far set apart. Four seems a waste of wood. That or the fence would be too high as it would be pointless. Three just works, I suppose.
Taken with Canon EOS 5D Mark II.
Canon EF 24-105mm f/4.0L IS USM at 95mm.
Shutter Speed: 1/100s.
Edited with Adobe Photoshop CS5.