The triangles are often identical in size, but they don't have to be. The joints connecting these elements in a truss are often called nodes. Trusses are ubiquitous in the construction of buildings and machines-for example, tower cranes are built almost entirely with trusses. The advantage of trusses is that they can form large, lightweight, and very sturdy structures while using only a handful of basic pieces to buid. Figure 11-37 shows a LEGO set that makes use of simple trusses