The Defects of a Place to Pace:

Native gloss: Jātaka, vol. i., p. 7, l. 14: Exempted from the five defects: The following are the five defects in a walking-place: hardness and unevenness; trees in the midst; dense underbrush; excessive narrowness; excessive width. For if the walking-place be on hard and uneven ground, then any one who uses it hurts and blisters his feet, so that he fails of concentration of mind, and his meditation is broken up; while he who walks at ease on a soft and even surface succeeds in meditation. Therefore hardness and unevenness of surface are to be reckoned as one defect. If a walking-place have trees in it, whether in the middle or at the end, then any one who uses it is liable, if not careful, to strike his forehead or his head against them. Therefore trees in the midst are a second defect. If a walking-place be overgrown with a dense underbrush of grass, vines, and so forth, any one who uses it in the dark is liable to tread upon snakes and other creatures and kill them, or they may bite and injure him. Thus a dense underbrush is a third defect. If a walking-place be excessively narrow, say only a cubit or half a cubit wide, then any one who uses it is liable to stumble at the borders and stub his toes and break his toe-nails. Therefore excessive narrowness is a fourth defect. If a walking-place be excessively wide, then any one who uses it is liable to have his mind wander and fail of concentration. Thus excessive width is a fifth defect. A walking-place should be a path a cubit and a half in breadth, with a margin of a cubit on either side, and it should be sixty cubits in length, and it should have a surface soft and evenly sprinkled with sand.

— Note in Warren, Buddhism in Translations, p9

Got'em all! That tree limb now bends lower to the ground so you will hit your head, the path is hard and crooked and is narrow (+ 1 cubit) and overgrown with weeds and it's only 48 feet in length.
[Edit: Friday, March 30, 2007 5:04 AM the limb came down of it's own in March 2006; the barrel and bamboo are long gone, there is a stone boarder which preserves a space of about a cubit on the up-hill side and back end.]
[Update as an Old Man, Tuesday, November 01, 2022 9:15 AM: I no longer use this place as my place to pace and it is now overgrown and almost invisible. I pace in a circle, inside my house, using my wheeled draftsman's chair as a walker. Not as satisfying, but I have no choice.]