The trees through the front window were older still: perfectly cylindrical Crayola-brown trunks, each supporting an acid-green cotton ball of undifferentiated foliage.

The walls and ceiling were perfectly cylindrical, and the floor was a long two-foot wide plank.

Both ahead and behind it stretched away, straight and perfectly cylindrical, into the darkness of the rock.

In both naturally occurring and synthetic porous structures, the geometry of pores and capillaries is almost never perfectly cylindrical.

If the rod is perfectly cylindrical, then the circular symmetry of the cross section makes it impossible to tell whether or not it is twisted.

And smack in the book's center shines the rabbit hole, white and perfectly cylindrical.

I found myself in a new 'well,' perfectly cylindrical in shape, and several hundred yards in diameter.

Perfectly cylindrical, they range from inches to several feet in diameter and depth.

No asteroid could have a perfectly cylindrical shape.

The attic, the space enclosed by the inner hull, was as perfectly cylindrical as a soup can with both ends removed.