Mid 20th century 'Congreve' rolling ball clock, sloped arch and pierced brass movement, the central Arabic minute chapter ring flanked by hour and seconds dials, twin train driven eight day movement, -
Idle-Tyme. The Original Rolling Ball Clock
How To Get Your Own Idle-Tyme. The Original Rolling Ball Clock
Bob Kojima's rolling ball clock
Ball Clock by Hex2000 | Download free STL model | Printables.com
Chronomeans - finest rolling ball clock ($7,000) : r/VeryExpensive