SYSTEMS OF STRONGLY COUPLED YO-YOS

A system of strongly coupled multiple Yo-Yos in series is disclosed in which very string that connects the successive Yo-Yos may be wrapped around Yo-Yos respective axles and therefore can be wound or unwound on both ends at the same time. Accordingly, both ends of the strings and their respective Yo-Yos may move with different speeds and accelerations. Yo-Yos in the system have a modular structure. The system also can be constructed with modular pieces to provide different operating modes when is set in motion. In embodiments, the Yo-Yos may be connected via the return strings. To ensure the Yo-Yo sides remain with equal length during the operation, a regulating mechanism is provided, and a regulating ring to keep the two sides of the return string in proximity, and assuring a long operation.