Under new rules in the District of Columbia, residents are allowed to possess, smoke, and grow marijuana, but they are not allowed to sell it. So, as Aaron C. Davis writes in the Washington Post, this presents an interesting question: How is the marijuana grown in D.C. supposed to get to people in the city who want to smoke it? And it turns out that in a few short months the enterprising people of Washington have found several opportunities:

A fitness instructor who took up the hobby six months ago has amassed enough pot to make tens of thousands of dollars selling it. Instead, he’s begun giving away a little bit to anyone who pays for a massage. The instructor asked not to be named out of concern that he or his home, where he sometimes serves clients, could become targets for criminals.

A T-shirt vendor in Columbia Heights who declined to comment may be working in a similar gray area. College students say the roving stand has become known to include a “gift” of a bag of marijuana inside a purchase for those who tip really well. And recently, dozens of people paid $125 for a class in Northwest Washington to learn about cooking with cannabis from a home grower. Free samples were included.

Andrew Paul House, 27, a recent law school graduate, may be the best early test case for whether home growers can find a way to make money from their extra pot.

House has started a corporation and a sleek Web site to order deliveries of homegrown marijuana to D.C. residents’ doorsteps — “free gifts” in exchange for donations to the company, akin to a coffee mug given to donors by a public radio station.

Davis goes on to examine other interactions between the law and natural human activity. The law, for instance, sets a limit on the number of plants people can grown in their homes, but it doesn’t limit the size of plants. Which allows for the production of more joints per month than you might imagine. Other growers have constructed sophisticated growing rooms. But note:

Many have tried to take a more organic approach to growing, using natural light and the ­District’s summer weather to bring plants to maturity. Those growers have generally had less success.

Prohibition of any activity that people want to engage in tends to fail. And however you define failure, it will always have unintended consequences. But in this case it’s pretty clear that the consequences of a confused halfway house between legalization and prohibition are better than the consequences of outright prohibition.