For those of us not affected directly by violence, a percentage of whatever measure of peace and joy we find in life is taxed away by ever-present news of senseless slaughter. Terror’s nightmarish images linger in our souls like the stench of dead fish washed up on a gorgeous beach. We live with anxious anticipation of the next tragic headline and fear that the world might ultimately descend into crazier and scarier scenarios. It’s easy to feel helpless. All the news about terror cells made me reflect on the human biological system. When harmful cells enter the bloodstream, they are swarmed by helpful cells. I imagine a world in which human beings join together in a worldwide immune system response, acting as compassion cells. To make this dream a bit more real, I designed what I call a compassion cell garden. I built it with my wife and children in our backyard. A few years earlier, I’d simply mowed the shape of it in the yard to get a sense of whether I’d be crazy to build it. That version, the kids said, looked like some sort of crop circle. I think it’s come a long way since then. Whe …