This unusual and intriguing digital clock is based on four rows of resin or steel balls, two rows for the hour and two rows for the minute. Although the balls move like those in a Newtons Cradle, only the outer balls on each row are suspended to swing; the inner nine roll on a track.
between groups of balls reveals one of the digits (such as the 4 in 6:49) that are otherwise hidden behind the balls. When an outer ball swings down and strikes a group of one to nine balls, the last ball in the group moves one position, and in so doing, covers the digit and uncovers a new.
It also transfers its energy directly or indirectly to the second outer ball, causing it to swing upward. As the second outer ball is then eased back into place, it can mechanically or electrically assist the first outer ball to swing up into striking position again.
One strike of the outer ball on the right increases the number on a row, but to return to 0, one to nine swift strikes of the ball on the left are needed, depending on the row. To ensure correct timekeeping, the fascinating, click-clacking clock must be placed level and must periodically calibrate itself.