“Clouds are not spheres, mountains are not cones, coastlines are not circles, and bark is not smooth, nor does lightning travel in a straight line.”

-Benoit Mandelbrot, The Fractal Geometry of Nature

Gas stations give way to empty lots on the outskirts, shredded plastic grocery bags flapping on razor wire. Saguaro cactus shadows lean long across the road. Behind the blue peaks clouds gather, but it’s full afternoon sunshine in the valley. Tucson’s sidewalks and gravel gutters sparkle with broken glass and mica. I’ve always thought it was pretty. Like glitter.

On the road out of town we pick up some chlorine for the Dome’s pool. “Got to kill off the critters,” he tells the guy across the counter, “Otherwise the bullfrog tadpoles make a mess of the place. They know a good thing when they see it.” Everything’s dormant in the desert until there’s water.

We pause a second too long at a red light. Dad’s hands have been shaking more in the past ten minutes. He checks his watch, brushes muffin crumbs out of his beard.

“Could you get me three of the blue ones and two round white ones?” I know how to pry open the child-proof bottles, count out the pills, and hand him the NASA constellation coffee cup without spilling on the bouncy road.

We’d stopped earlier that morning at the chemistry department to pick up the next round of meds for the FDA trial. The researcher’s rumpled pastel polo matched my father’s. “We’re having trouble finding trial participants because the side-effects include incontinence and uncontrollable tremors.” “Tough shit!” Dad barked, “That’s what I’ll get with this damned disease anyway. What have I got to lose—my continence?” He cracked a grin.

We’re almost to the mountains. Dad’s telescopes are up there, in the university observatory. Sometimes you can see them, tiny pinpricks of white against the blue mass of the mountain ranges lining the valley. Thunderstorm clouds are billowing over the mountains. “We’d better be quick–going to rain.”

The crunch of gravel in the driveway mutes the aria on the radio. There’s the Dome: hunched spherical house of brown shingles and angular planes of glass. It blends with the dusty mountains. Buckminster Fuller‘s geometric design in the Sonoran Desert. Dad says he needed a minute for his meds to kick in, stays in the driver’s seat, leaving the truck rumbling on idle. I hop down from the cab and slam the door–squeak and shut, a mesquite branch scratches the door. I can smell the creosote rising from the ground. The desert is still, but alive. Cicadas buzz, thunder rumbles in the distance.

Walking around the circular foundations of the Dome, I pick up a dessicated saguaro rib to poke at stuff. There are cool sunken holes around the base of the barrel cacti –snakes and spiders’ homes. I look into the ordered tangle of spines at the top of a barrell cactus. Perfect synchrony, perfect spirals. Some forms are simple.

“Hey, don’t wake up those snakes!” he croaks from the truck. His voice is strained. “They’re sleeping, leave them alone to do their thing.” He used to sing in the opera chorus; now when he’s off his meds his voice barely rises above a whisper. I roll my eyes and walk around to the other side where he can’t tell me what to do. Whatever.

On the other side of the sphere the light slants pink in the afternoons. There’s a rosy tint on the bricks my dad laid, the remnants of a desert garden my mother tended. Tucked in a corner, the improbable night-blooming cereus: a scraggly desert plant that produces a showy orb of glowing white petals for a single summer night.

Dad gets out of the car with his grey cane and shuffles slowly over to the walkway, counting his steps “one-two-three-four,” leaving dragged footprints in the dust. The counting helps him walk.

This dome creeps me out. I’m glad not to be alone around it. Two half-shells: a concave scooped swimming pool and a convex geodesic dome. I have photo albums of my parents living here, throwing parties with friends from the Arizona Opera company, running around naked and sunburned, having crowded picnics in the arroyo just after a flood, smoking during dinner parties on the curved patio.

“Crack one of those Coronas? My hands are still shaking too much. I need to check on the pool.” We walk round to the front, peer inside the dusty triangular windows–red shag carpeting, round Noguchi paper lamps, floral sofa. He never did redecorate after my mother died, during night-blooming cereus season. Dad doesn’t want to sell the Dome. It took years for him to get rid of the everyday things she left behind: her toothbrush, a half-sewn Opera costume corset. Now he rents it or leaves it empty.

The heat from above is like a furnace. Hot white light. We open the door and a blast of hot, stale air rushes out. She was alone for two days. Well, I was alone for two days with her. Ten years ago Dad had been on a work trip, and he got the news from a neighbor: she’d come by and found his baby alone with his dead wife. That night the cereus bloomed. The year-and-a-half-year-old had drunk Draino and Windex and whatever else she could find under the sink. The mother’s body dessicated in the desert heat. “The smell...” “Heart attack.” Tragedy. “Only forty-one.” Gossip and generosity. Homemade casseroles, flowers, unannounced visitors, letters of condolence, offers to babysit, insistence that the child be raised by well-meaning aunts, lots of quiet dinners made of scrambled eggs because they were easy to cook.

So when his body began falling apart, a diagnosis the same year my mom died, he just kept going. He received a prognosis that he wouldn’t last to see his daughter through middle-school. “Well, shit.” This is nothing—he’s been to zero-G, floating in space with the astronomy department. He refuses to quit, which means he’s only half dying. He’ll go down kicking.

I ask him what it was like floating in zero-gravity. “The desert is beautiful from high above. Imagine all those infinite little arroyos on the desert floor, spiraling out from canyons in the mountain ranges.” Like arteries in a body. Dried up. Fallible. Layers of skin, tissue, and bone that make up a human body. How permeable. Utterly transient.

“It’s like this thing is mocking me.” He struggles with the chlorine tank at the edge of the pool. Sometimes we talk about whether it would be better to just go quickly, in your sleep. I like it when he treats me like an adult, like someone who knows her own mind. “At least we know she went peacefully,” he’d said last year. “Just step on my cord if I ever get to the point where I don’t know what’s happening. I don’t want to be a vegetable. What’s the point? Just step on my cord.”

He’s kept the Dome in limbo. A half-inhabited house. He doesn’t live there, but won’t let go of it. He can’t climb the ladder anymore to get to the loft beneath the arch of the ‘omni-triangulated’ ceiling. We live in the city, in my stepmother’s big house full of dusty antiques. Her flat-backed bookshelves wouldn’t fit against the sphere’s round walls.

The Dome is falling into disrepair: there’s a wolf spider living in the shower drain and the packrats have made a nest in the chimney out of barbed cholla cactus branches. “Resourceful buggers,” he’d said last summer, poking futilely at the dense mass of impregnable cactus with the vacuum nozzle.

A crack of lightning sears the sky. “We’d better get inside.” He drops the chlorine tank back in and lowers the lid. “Twelve, thirteen, fourteen….” Boom. “The storm’s about to hit!” We count the seconds between the clap of thunder and the next flash.

Now he’s running back into the dome as the first claps of thunder roll across the valley. I race after him, my flip-flops slapping as the first raindrops are evaporating on the hot bricks. Sometimes with Parkinson’s it’s easier to run than to walk. We take refuge within the dome’s arched geometry. A perfect tangle of angled windows and triangular panels. It feels remote inside, like we could be on the moon.

“Got to watch out for that–lightning and water. Don’t want to get zapped. Remember wiring the electrical current in the 4th grade science project? It’s the same idea. Lightning takes the quickest path to the ground.”

“Does lightning always follow the same pattern, like the cactus spines or snowflakes?”

“No–it’s following basic laws, but the path is unpredictable.” A crack of light. We count. “Four, five....” Thunder hits. “That was a close one.” He hands me a towel; I wipe off wet sunscreen.

“How do we know if it’s unpredictable? Same way they know how long the new meds will last?”

He takes a swig from the Corona. “Yeah, something like that. They’re saying six months.” He picks at the cactus spines in the red shag carpet, fidgeting. “These prickers–what a mess.”

I count out on my fingers: August to May. “The night-blooming cereus is only ten months away. Will you bring me out here when it blooms?” Rain pounds on the skylight. The housecats used to sleep on top of the skylight. The smart ones, anyway. The ones that didn’t get eaten by coyotes.

“Yeah, if these goddamned legs make it that long, I’ll be there. This stupid cane. My legs can’t decide whether they want to stay or go. It’s like watching your body disintegrate. High pressure in slow motion. Pulls you apart. I’m sorry, I shouldn’t be telling you these things. You’re just a kid.”

“Hey, I’m twelve this summer.” He chuckles.

“Gotta keep trying new meds. There’s a new one coming out soon–already approved in Europe. Ed down at the university said we’re running out of time to test it.”

“It’s not fair. I wish you weren’t doing the med trial. It makes it worse. Wish we just knew how much you had left.”

“How much we have left before the next boom of thunder?”

“Yeah–and when the night-blooming cereus will happen. And whether your legs will make up their mind.”

He laughs, wipes beer off his moustache. The light changes before the thunder stops. Rain lets up; the sky takes on an eerie red glow. “Want a sip?” “Sure.” Creosote and wet sunscreen stings my nostrils. We dry off and crunch our way back out to the pool. Red bricks blackened by rain, steaming.

In the desert he sees patterns everywhere, and shows me. Fractals spiraling out of celestial galaxies. Geodesic dome structures raised out of the desert. Fibonacci patterns in barrel cactus spines. Order in the night sky.

The cereus plants all bloom at once. Nobody knows how the blooms all happen at the same time, for those few hours. Maybe a gust of wind or a change in barometric pressure, and you won’t get the chance to see it. Early next summer, on some unexpected night, we’ll get a neighbor’s phone call. Bloom night. We’ll drive out the bumpy desert road at sunset, evening drawing darker as the constellations arch overhead.