One of the most basic tricks is called the sleeper, where the yo-yo spins at the end of the string for a noticeable amount of time before returning to the hand.

[3] Greek records from the period describe toys made out of wood, metal, or painted terra cotta (fired clay).

[3] The terra cotta disks were used to ceremonially offer the toys of youth to certain gods when a child came of age—discs of other materials were used for actual play.

[citation needed] In 1928, Pedro Flores, a Filipino immigrant to the United States, opened the Yo-yo Manufacturing Company in Santa Barbara, California.

[4] The business started with a dozen handmade toys; by November 1929, Flores was operating two additional factories in Los Angeles and Hollywood, which all together employed 600 workers and produced 300,000 units daily.

In Flores's design, one continuous piece of string, double the desired length, is twisted around something to produce a loop at one end which is fitted around the axle.

Also termed a looped slip-string, this seemingly minor modification allows for a far greater variety and sophistication of motion, thanks to increased stability and suspension of movement during free spin.

[citation needed] Declining sales after World War II prompted Duncan to launch a comeback campaign for his trademarked "Yo-Yo" in 1962 with a series of television advertisements.

[citation needed] In a trademark case in 1965, a federal court of appeal ruled in favor of the Royal Tops Company, determining that yo-yo had become a part of common speech and that Duncan no longer had exclusive rights to the term.

[12] As popularity spread through the 1970s and 1980s, there were a number of innovations in yo-yo technology, primarily regarding the connection between the string and the axle.

While the yo-yo is in the "sleeping" state at the end of the string, one can then execute tricks like "walk the dog", "the elevator", "around the world", or the slightly more complex "rock the baby".

The two main ways to do this are (1), allow the yo-yo to sit at the bottom of the string to unwind, or (2) perform lariat or UFO to loosen the tension.

When one decides to end the "sleeping" state, one merely jerks the wrist and the yo-yo "catches" the string and rolls back up to the hand.

[citation needed] Modern yo-yo notation is designed to be ambidextrous, further eschewing terms like "clockwise" and "counterclockwise".

Eventually, wider string gaps and silicone response systems led to the innovation of unresponsive yoyoing, otherwise known as 1A.

This has brought about innovation of many different kinds of tricks involving leaving slack in the string, as this would have caused a responsive yoyo to return to the hand.

[24] Yo-yos optimized for looping have weight concentrated in their centers so they may easily rotate about the string's axis without their mass contributing to resistance due to a gyroscopic effect.

Popularized and pioneered by Mark McBride, the first modern Triple A trick appeared in Fiend Magazine and was called the Velvet Rolls.

While 3A as a concept has existed for many years, it was not until the debut of Velvet Rolls, coupled with the rise of unresponsive yoyo play, that development began on what is currently considered Triple A.

Yo-yos optimized for off-string tricks have flared designs, like the butterfly shape, which makes it easier to land on the string, and often have soft rubber rings on the edges, so minimum damage is inflicted on the yo-yo, the player, or anyone who happens to be standing nearby, should a trick go wrong.

Steve Brown was awarded a patent on his freehand yo-yo system, which was assigned to Flambeau Products (Duncan's parent company).

Modern responsive yo-yo can be thought of as 2A with a single yoyo, but differs from 2A in the fact that it, like 1A, has access to tricks involving the use of the free hand.

Unlike 1A, modern responsive deliberately abstains from tricks that involve sleeping, frequently replacing mounts with stalls.

In this case, the yo-yo will continue to spin in the loop at the end of the string (or sleep), just being slightly braked by the small dynamic friction, instead of returning.