If you’ve ever looked at the 64 hexagrams of the I Ching you may have noticed a resemblance to stacks of stones. Each hexagram is a different arrangement of six lines, some solid and others broken in the middle; a little like a wall with random gaps between stones. It’s the randomness that lends fair form to the divination process represented by the I Ching, a 2,500 year old system of consultation. Tossing Yang or Yin is the basis of the “Book of Changes”, as the I Ching is known in English.

The past few weeks I’ve tossed my lot in making changes on a New Hampshire hilltop. It wasn’t the first time a collection of stones there was strung across the high mowing. Someone came in the 19th century and flung up a wall, divining meaning from the random arrangement of stones as they fell into place. And then it was my turn to interpret the stones. The old, sunken wall line coughed up bucketful after excavator bucketful of fieldstone. After spreading the stones out on the frozen ground so I could get a good look at the variety of shapes and sizes, I chose a fair form for re-assemblage.

With every stone’s length laid across the wall, largest on the bottom, smallest on top, one stone thick throughout, the fence rose. It can be described as a “lace” wall because it’s shot through with holes. Each stone touches its neighbors, beside and below, just enough to fix it in place with nothing extra. In winter, the holes let the wind whistle through while the snow, carried by it, stops and drops in drifts along the wall line instead of settling across the field beyond. The old fence was built low and wide to consume tons of stone picked from the field. The new fence is built tall and narrow to drift up the snow in wintertime and stand proud of the hay stems in summer. In 150 years the land has tossed the I Ching twice, the old wall came up Yang and the new one, Yin.