There are many structures whose individual members are made up of  beams. Some

 
There are many structures whose individual members are made up of  beams. Some examples include bridges, skyscrapers, artwork, signs,  parking covers, and even furniture. These beams are intentionally  designed with different cross-sectional shapes to optimize both  strength, and weight all depending on the type of loading condition they  will be subject to. As an engineer, it is our responsibility to  consider the loading conditions of the structures we design then to  select from the available beam geometries a shape and size that will be  more than strong enough to last. 
Common Beam Cross-Sectional Shapes
Statics allows us to quantify the loading conditions and use the  support types to understand the forces and moments a beam must be  designed to hold. Each symbol of a support type correlates to real-life  connections that are commonly used in structural design. In some cases,  support types that become too constraining create a statically  indeterminant situation where statics is not enough to solve for the  forces and moments on a structure. 
Structures and Members
In your original post, include the following:
Find a real-world example where beams are used in a structure and identify/discuss the following as they apply to your example 

Beam type
Support types
Loading type