The Three Sisters

Southwestern Mexican/Indian populations historically grew a combination of vegetables known as "the Three Sisters": corn (maize), squash, and beans. The corn stalks grew tall, the squash grew low and provided shade and cooling for the soil while blocking weed growth, and the beans trailed up the corn stalks using them as a natural trellis as well as fixing nitrogen in the soil to feed the corn, a heavy nitrogen user. The U.S. Mint even produced a $1 gold coin commemorating the Three Sisters" on the reverse side:

Joel Gruver, professor of agriculture at Western Illinois University, uses backyard wading pools to create raised garden beds. I noticed in a series of pictures he posted on his beds project (here and here) that he is growing the Three Sisters in one: beans in the outermost circle, corn in the middle circle, and squash growing in the middle. Very creative! Something anyone could do to create a YardFarm in their own urban or suburban setting:

(Thanks to Joel Gruver for the use of the pic of his growing pool.)

Update: I heard from Joel -- his variation on the "Three Sisters" was that the beans were bush beans instead of climbing (pole) beans, and the center planting is cukes instead of squash (the starter leaves on both plants are similar, so I had assumed squash). He said the corn was a tropical variety that got over 12 feet tall (!) planted in the pool. The cukes didn't fare as well because of the shallow soil and need for continual watering. But, as the pics I linked to above testify, the pools are perfect for growing mesclun mix and other salad greens that require less depth.)