Image courtesy ©Lego A standard LEGO brick has studs on top and tubes inside.

Nathan Sawaya has created a life-sized replica of Han Solo frozen in carbonite. He's also made an 8-foot-tall pencil, a Statue of Liberty holding a lightsaber, a Golden Gate bridge and a Tyrannosaurus Rex. And he's done it all with LEGO® bricks. What does it take to turn a pile of 10,000 bricks into Han Solo? Where do the bricks come from, and what makes them stick together? And how did a free-form building system evolve to include programmable bricks, replicas of the Death Star and the Batmobile, and printed instructions?

In this article, you'll learn lots of brick basics as well as how Master Builders and devotees make enormous creations out of tiny bricks.

Most LEGO pieces have two basic components -- studs on top and tubes on the inside. A brick's studs are slightly bigger than the space between the tubes and the walls. When you press the bricks together, the studs push the walls out and the tubes in. The material is resilient and wants to hold its original shape, so the walls and tubes press back against the studs. Friction also plays a role, preventing the two bricks from sliding apart. This stud-and-tube coupling system uses an interference fit -- a firm, friction-based connection between two parts without the use of an additional fastener.

All of the basic LEGO elements use this principle to stick together. They come in a range of shapes and sizes, including wheels, windows, doors and studless tiles. But the basic elements are all variations on the basic brick. You can learn about the basic LEGO elements in our field guide below.

You can make a 2 x 2 brick with three 2 x 2 plates or a 2 x 4 brick with three 2 x 4 plates. Or, you can combine 2 x 2 bricks and plates to make a 2 x 4 brick.

Image courtesy ©Lego Basic LEGO elements begin as blue, black, dark grey, green, light grey, red, yellow and white.

All of the basic LEGO elements start out as plastic granules composed primarily of acrylonitrile butadiene styrene (ABS). A highly automated injection molding process turns these granules into recognizable bricks. The making of a LEGO brick requires very high temperatures and enormous pieces of equipment, so machines, rather than people, handle most of their creation.

Image courtesy ©Lego The injection-molding process uses large, heavy molds that are manufactured in Germany.

Image courtesy ©Lego Molded elements fall into bins and wait for a robot to carry them to the assembly hall.

When the ABS granules arrive at LEGO manufacturing facilities, they're vacuumed into several storage silos. The average LEGO plant has about 14 silos, and each can hold 33 tons of ABS granules. When production begins, the granules travel through tubes to the injection molding machines. The machines use very accurate molds - their precision tolerance is as little as 0.002 millimeters.

The machines melt the granules at temperatures of up to 450 degrees F (232 degrees C), inject the melted ABS into molds and apply between 25 and 150 tons of pressure. After about seven seconds, the new LEGO pieces cool and fall onto a conveyor. At the end of the conveyor, they fall into a bin.

Image courtesy ©Lego To create a LEGO brick, an injection-molding machine applies between 25 and 150 tons of pressure to a mold containing melted ABS.

When the bin fills, the molding machine signals a robot to pick it up and carry it to an assembly hall. In the Billund factory, eight robots move 600 bins of elements per hour. In the assembly hall, machines stamp designs onto bricks and assemble components that require multiple pieces, like minifigures, also called minifigs. The machines assemble the components by applying precise amounts of pressure to specific parts.

Image courtesy ©Lego Machines assemble components that require several pieces, like minifigures

Recycling LEGO factories recycle all but about 1 percent of their plastic waste from the manufacturing process every year. If the plastic can't be re-used in LEGO bricks, it's processed and shipped elsewhere.

From there, the elements go into packages. If you've bought a LEGO set -- whether it's a box of assorted bricks or a set meant for building something specific -- you've probably noticed that the box includes several bags of bricks rather than a large pile of loose elements. These bags are part of the automated packaging process, and they help make sure that the right pieces go into each box.

Image courtesy ©Lego Finished LEGO elements wait to go into packages in a storage facility in Billund, Denmark.

Image courtesy ©Lego Quality assurance testing ensures that LEGO parts are durable and will stand up to lots of play.

During the packaging process, bins open and close automatically, dropping precise numbers of bricks into each polypropylene bag. A machine weighs these bags to make sure their contents are correct. If a specific bag's weight is incorrect, an operator can replace that bag, rather than having to discard an entire set.

At the end of the process, packaging operators fold the boxes, add any necessary pieces and make sure that the machines haven't made any mistakes. The sealed boxes are stored and shipped around the world -- the process uses between 400,000 and 500,000 cardboard boxes per year.

Quality assurance testers also perform numerous inspections and tests on LEGO elements. Machines perform drop, torque, tension, compression, bite and impact tests to make sure the toys are sturdy and safe. Technicians use a measuring beaker to determine whether pieces could cause a choking hazard for small children. For every million LEGO elements, about eighteen, or 0.00002 percent, fail to pass the tests.

A Brief History of Tubes In 1949, Danish toymaker Ole Kirk Christiansen introduced Automatic Binding Bricks, a precursor to modern LEGO bricks. These plastic bricks didn't have interior tubes, so creations built with them weren't very stable. The company added tubes to the basic brick in 1958 and patented the design. Basic LEGO bricks have remained unchanged since then - brand new bricks are compatible with the ones produced in 1958.

Much of the manufacturing process takes place in Klando, Czech Republic and Billund, Denmark. All in all, LEGO factories produce 33,000 bricks every minute, for a total of 16 billion bricks every year. The manufacturing facilities can make 3,000 different types of elements, including 300 million tires, and these pieces go into 37,000 LEGO sets every hour.

Special Thanks Thanks to Nathan Sawaya and Kristin Greene for their assistance with this article.

In the next section, we'll look at what you can do with all those finished bricks.