You're probably thinking of a rotary growing system. There's a few different brands but it's basically a wheel where the plants sit on the inside and rotate around a light suspended in the center. I've heard it's the hardest way to grow because you've got to get everything just perfect, from the construction to the heighth of the plant and pretty much everything else. There's been a few posts of people who've bought them, but I've never seen a grow journal with one. Would be pretty cool to see though.