My name is Jens Bergensten, but I'm better known as Jeb. I'm the lead developer on Minecraft
here at mojang.com. I think I was 11 or maybe 12 and I started programming because I wanted
to make games. One of my father's friends told me that in order to make games you need
to learn how to program. So that's how I got started. I like designing and figuring out
the architecture of things. That's what I really like about Minecraft. Over the next
hour you're going to learn the basics of computer science by programming Alex or Steve to move
through a simulated piece of a Minecraft world. Traditional programming is usually in text,
but today we'll use blockly: a system which uses blocks that you can drag and drop to
write programs. Under the hood, you're creating JavaScript code. The concepts that you'll
be learning are what computer programmers use everyday and are the foundation to computer
science. Here at Mojang we use these same concepts to make Minecraft work. Before you
start, you'll pick your character. I'm going to choose Alex. Let's build code for a program
that will help her move around the screen. Your screen is split into three main parts.
On the left is the Minecraft play space, where your program will run. The instructions for
each level are written below. This middle area is the toolbox and each of these blocks
is a command that directs Alex's actions. The white space on the right is called the
work space and this is where we'll build our program. If we drag the \"move forward\" block
to our workspace and then click Run, what happens? Alex moves forward one space on the
grid. And what if we wanted to do something after she moves forward one space? We can
add another block to our program. I'm going to choose the \"turn right\"; block, and I'll drag
it underneath my \"move forward\" block until this orange line appears. Then, I'll drop
it and the two blocks will snap together. When we press Run again, Alex will perform
the commands that are stacked from top to bottom in our workspace. And if you ever want
to delete a block, just drag it from the stack back to the toolbox. To undo your changes
and to get back to how the level started, use the Start Over button in the top right
corner of the workspace. One more thing, you see the little triangle on the turn blocks?
Anytime you see these triangles, it means that you can pick a different option. Let's
start coding!