Stanley Strum is spending his time in class today building a TARDIS, the time machine from the TV show "Doctor Who."
"The machine pretends to be a telephone box, but actually it's an infinite, ginormous, thing on the inside," he explains.
Strum, a fourth grader, is building this TARDIS out of blocky pixels — kind of like digital Legos — in the world of Minecraft.
Last week, Minecraft's parent company was bought by Microsoft for $2.5 billion. With 54 million copies sold, the extremely popular video game has become an industry unto itself. An industry that even includes education.
"It's a game about building things," says Stephen Foster, CEO and co-founder of a San Diego company called ThoughtSTEM that aims to introduce kids to the basics of computer science through games.
"You can use code to build cool things in Minecraft that you couldn't do by hand or it would take you days to build by hand," he said.
There's a few ways to play Minecraft. In survival mode, you have to gather natural resources, build a home base and fend off monsters. But in creative mode, you're free to do just about anything. Or, as Stanley Strum puts it, "You have infinite items, you have infinite health, and you build whatever you want."
Because Minecraft is so open-ended, kids can easily get lost in the game for hours. But that openness also makes Minecraft a great educational tool, according to Stephen Foster.
ThoughtSTEM's Minecraft class is by far its most popular. Two hundred kids have taken this course since it launched in March. Demand was so high, they had 100 people on the waitlist before classes even started.
At the beginning of one of their Saturday courses, the instructor pulls up a window with strings of colorful, moveable code. He explains how each line on the screen will modify — or "mod" — the world of Minecraft. Instead of painstakingly digging a tunnel, or constructing a huge tower block by block, they can use code to build wild, elaborate structures.
"Which is exactly what computer science is good for for adults as well," Foster said. "That's half of what I do as a coder, is I code things so that they happen automatically rather than having me do them by hand."
ThoughtSTEM grew out of Foster's research into games and education as a computer science doctoral student at UC San Diego. He's been building another game from scratch called CodeSpells. Kids play as a wizard who casts spells through the magic of code.
That game is picking up steam. Foster and his colleagues launched a Kickstarter this month, and they've already pulled in more than double their fundraising goal.
But students kept nagging Foster about Minecraft modding. He realized he needed to tap the potential in this huge, established fandom.
"If you interview a lot of the parents of kids in this class, many of them are bringing them here because they want to channel the hours they spend on Minecraft toward something interesting and academically productive," Foster said.
And because Minecraft has such broad appeal, you see something here in rare supply for other coding courses: girls.
The gender disparities in computer science are huge. Less than 15 percent of college computer science graduates are women.
Educators hoping to narrow that gap are asking: How can we get more girls into coding? ThoughtSTEM hasn't solved the problem yet. Classes still skew male, but Foster says Minecraft opens up coding to all kinds of kids.
"Minecraft is very un-gendered," he said. "It's not about destroying things or people, it's not about trying to establish dominance over opponents. It's just about building things and often building things with your friends. There are definitely plenty of girls who play it. So if you want to get more girls into computer science, I think Minecraft is a way to do it."
But Minecraft wouldn't help anyone learn to code if it were like most other games — walled off and impossible to customize. The game could be in for some changes under its new owners, Microsoft. Fans are wondering, will Microsoft push more users to buy their XBox console for the best Minecraft experience?
"I think that's the question on everyone's mind," Foster said. "Is Microsoft going to ruin Minecraft somehow? If they come and decide that only a few people are able to play Minecraft, like the ones on Xbox, then that would certainly be bad for us, but also for almost the entire Minecraft community."
Foster doesn't think Microsoft will ruin Minecraft. He thinks it's not in their interest to alienate kids like Stanley Strum, who says the only thing better than playing Minecraft is modding Minecraft:
"When you really want to do things, you go here, and then you just start modding and having fun," he said.
