The 50/50 Pizza truck lets you play a game of chance before digging into a pie. (Tim Carman/The Washington Post)

The prize wheel isn't one of those hand-cranked spinners with a clicker on top and a teeny-tiny sliver devoted to the only gift anyone would care to claim. No, this is an electronic iPad prize wheel, and half the slots will earn you a 99-cent pizza.

There's a caveat: You have to hand over your cash or credit card first. It's the only way that John Lewis, the lone man working the 50/50 Pizza truck, can guarantee you won't walk away if the needle lands on the other option: a \$9.99 pie. The new vendor, after all, couldn't survive a week on the streets if it hawked only \$1 pies.

50/50 Pizza may be the first food truck based on probability and statistics. Owner Jean-Max Buteau, 24, is a Haitian native who left the country shortly after the devastating earthquake in 2010. He eventually landed at American University, where he graduated with a degree in systems engineering and business administration. He's fascinated by statistics and the laws of probability.

But Buteau is also the son of parents who ran hotels and a catering business back in Port-au-Prince. He was interested to see if he could build a food business around the laws of probability. The concept was simple: Allow customers to spin a wheel in which the odds were 50/50 that they would receive a deeply discounted lunch. While a single spin could be a boon to customers, the collective spins would be a boon to Buteau.

“Take a look at the laws of probability,” says Buteau, a contract financial analyst for the State Department. “If you spin this 100 times, it's going to spin 50 times on one color and 50 times on the other.”

A pizza from the 50/50 Pizza food truck. (Tim Carman/The Washington Post)

All Buteau had to do was select a dish whose median price would generate a profit. He went with pizza. It happens to be Buteau's favorite food. But more important, “pizza was the cheaper to prove the concept and kind of make it a fun experience,” he says.

Cheap, of course, is key to street food, no matter what you're selling. But cheap is vital when you're planning to give away approximately half of your meals for less than cost. You have to make sure the full retail price of your product covers not only your costs but also the losses from the other half of your sales. Plus, the full retail price can't be so ridiculously high that customers would flee like bunnies at the sight of it. (I should point out that both the 99-cent pie and the \$9.99 pie include only one topping; additional toppings are \$.99 each.)

“Every two pizzas cost me \$11,” Buteau says, “which still leaves me with a profit margin, no matter how many I sell that day.”

Pizza is the smart choice: Its primary element, the crust, is basically flour, water, sugar, salt and oil, or a variation of those ingredients. 50/50 Pizza prepares its dough at Union Kitchen and immediately portions it into individual balls, which then rise for a minimum of 12 hours. Buteau prepares the dough, and Lewis handles the zippy cooked tomato sauce with red pepper flakes and roasted red peppers.

It's DIY all the way at the 50/50 Pizza truck. (Tim Carman/The Washington Post)

There is no set menu at 50/50 Pizza. Once you spin the wheel — actually, you press a button on the iPad, but whatever — and learn the price of your lunch, you must cobble together your own pie from a list of ingredients. Don't expect house-made 'nduja, okay? These are basic, commercial-grade ingredients, the best you can buy for \$5.50 a pie. The rounds are crisped up in a Bakers Pride deck oven right there in the truck, an impressive piece of onboard equipment.

So far, I've ordered three pizzas from 50/50 (two for \$.99, so I'm ahead of the game!). They're serviceable at best, the dough only moderately developed but the sauce bright and spicy. I mean, I won't be changing my allegiances from 2Amys or Frankly...Pizza! any time soon, but I'd return. Half the fun is the electronic roulette wheel that starts the ordering process.

There's nothing like a game of chance before lunch.

The 50/50 Pizza truck vends Monday through Friday. Check out its website for locations.