Basic Lego bricks are full of 90 degree angles, but finished products aren't limited to squares. With enough 90 degree angles close enough together, you can make objects that incorporate spheres and curves. With enough bricks, you can build pretty much anything.
But anyone who has been to a toy store recently knows that Lego pieces are no longer limited to basic bricks. New sets include customized pieces like wings, sails and masts. Some sets, like BIONICLE and KNIGHTS KINGDOM sets, are designed for constructing models that resemble action figures. TECHNIC sets let you turn a Lego creation into a machine by adding studs, axles, motors and gears, and MINDSTORMS sets let you build programmable robots. The FRIENDS line, which drew controversy upon launch, is marketed toward girls and features a beauty salon, a veterinarian's office and a restaurant, among others.
So, if you want to build something really impressive, you can buy a kit that includes all the pieces and step-by-step instructions on how to put them together. Or, you can buy lots of bricks in a variety of shapes and sizes, and figure out how to build them yourself. Building from a kit is pretty easy -- the instructions don't even use words, and if you lose your instructions you can download a new set from the Lego site.
In the next section, we'll focus on what it takes to design and build your own creation.