Over the past several winters, the hill north of our house has become the favorite place in the neighborhood for sled riding. Starting at the garage, the lane curls down in a sharp C-curve, then straightens just long enough to go into a second curve curling the other way. It then levels out into a broad expanse of flat pasture, where tubes and sleds have plenty of room to slow down to a relatively safe stop.

One day last winter I looked out the family room window and saw gangly Ben Hadlock poised at the top of the hill on a home-built contraption, the likes of which I had never seen.This was not a surprise. Ben, who is 14 or 15 now, is renowned for his obsession for contraptions. Apparently he got not only his father's right-brainedness (Neil, his father, like myself, is an artist), but along the way they both picked up a goodly portion of mechanical good sense. Ben's grandpa is an auto mechanic of the old school, and his great-grandpa was a blacksmith.

An example of Ben's prowess occurred two or three years ago at Christmastime. I walked into Neil's studio and there was Ben (I think he was barely 12 at the time - if that) madly at work on a gumball machine of his own design. It was a flat affair, made of wood with a clear Plexiglas front so you could see all the working parts.

It had a device that took a nickel through a slot, which then allowed a circular thing to turn, which dropped the nickel into a hollow in the bottom, at the same time allowing one gumball to pivot from a gumball container area at the top, down through a series of zigs and zags and out the bottom onto a little liplike shelf outside the machine before your eyes.

It was such an immaculate machine in both form and function that I had him build me one for Christmas. It now sits here in the corner about 5 feet from where I write and is slowly turning into a neighborhood heirloom.

But back to the sled contraption.

Ben had taken a couple of old mismatched skis and, with a few grabber screws and several pieces of scrap lumber, had created a tri-sled with a seat and a place to put your feet on a turner device in the front for steering the thing.

In his first test ride, to which I happened to be privy through my secret observation post in the family room, the machine acted a bit skittish, sliding a little to the side and not steering to Ben's satisfaction. It was intriguing to watch him study and caress his invention into being, giving a whack here and a twist there. It was not a forced process. His mind was obsessed with the proj-ect at hand, which he went about with confidence.

Neil says Ben has always been like that, from the time he was little. Sitting in class drives the kid up the wall, and school is a real struggle for him. I can almost picture him in a school desk, the perfect picture of a man in a medieval torture device, twisting and writhing in agony as the clock ticks away toward 3.

Within hours, the tri-sled was old stuff, and Ben was on to other things. The smaller kids in the neighborhood, however, relished the thing all winter.

I came across Ben's tri-sled the other day. Leaning up against the side of a box elder tree on the edge of the pasture, it looked awkwardly out of place in the newly sprouting grass and warm sun of late spring.

Currently, Ben is on a motorcycle kick, not the big Harleys or BMWs, but a cast-off little putt-putt thing that he saw in a kid's back lot covered with grease and rusting to death. It was in such bad shape that the other kid was willing to trade it for a used skateboard.

Within two days, Ben had stripped the thing to bits, totally reworked the carbur-etor and engine and, though it was minus half the spokes in the front wheel, had it running like a charm. (He resolved the spoke problem by spreading out the good ones between the two wheels.) Now Neil is scratching his head to try to figure out how to draw in the reins.

The bad spokes may have given him a brief reprieve.

Last Monday night several families in the neighborhood were having a wiener roast down by the pond. Ben was giving kids rides in the pasture, and somewhere in the dusky evening they all got onto the idea of seeing how many could ride the thing at one time. It was a hoot to watch them, four and five deep plowing through the grass with legs sticking out every which way.

If it had been a pony, the act could easily be labeled as inhumane. As it was, I couldn't help but guess that Neil was hoping down deep that somewhere in the dim light of evening on a safe cushion of pasture grass the spokes would give out on the whole affair.

The spokes held - for the time. But yesterday Neil mentioned with the slightest glint of a smile that the motorcycle had gone kaput - something about the back wheel and the spokes or something. I detected in his voice a sigh of relief - for the moment.

I'll be interested in 20 years to see what Ben ends up doing with all his thinking and energy. I have a feeling that we have seen only the first few scenes of a fairly long and interesting production.