It looks simple: Two tiny buckets fastened together with a common top and a single central opening.

Aenea followed him to the stairwell, kicking over to the central opening.

Peytoias are sometimes associated with the appendages; these have a square central opening.

"Always we take the central opening and climb upward."

This is the central circular opening in the colored part of the eye - also called the iris.

The front used differing column distances, with a wider central opening.

Below us was the second floor with its corresponding central opening.

As the liquids enter the central opening of the rotor, they are accelerated toward the wall.

The central opening, larger than the side ones, is supported by free-standing columns.

So I chose the central opening, and passed on into its gloomy depths with a prayer upon my lips.