I find that interlocking cubes such as Multilink or Centicube are an excellent resource for exploring shapes in this way. Children have the opportunity to make, break and re-make shapes while considering their properties and the best way of representing them.

Try these activities with your class. 

Shape footprints

How many different shapes can be made with 4 cubes that will fit on this shape footprint (shown to the right)? What about 5 cubes?
 
There are more shapes than you may think, although some shapes will tip-over without support. You can decide whether to include these.
 
Once a group of children have found all the possible shapes, ask them to work in pairs.
They take turns to ‘explain’ their shape to their partner using only written instructions or drawings so that they can make the shape with cubes. These drawings can be their own invention and may be a little inaccurate - although they should be encouraged to try different methods.

Plans and elevations

Once children have explored their own recording of shape footprint models, demonstrate the drawings of front and side elevations alongside the plan. Talk about the reasons why these are useful as they show accurate representations of shapes.

Here is an example, using a shape made with 5 cubes:

Plan



Side elevation



Front elevation