Shuffles are either synchronous (commonly referred to as "sync") or asynchronous ("async"), depending on whether the diaboloist's hands' movements occur simultaneously or not; shuffles may also be performed with only one hand. Juggling multiple diabolos "high" involves continuously catching and throwing a number of diabolos, never with more than one diabolo on the string simultaneously. Diaboloists have pushed the number of diabolos juggled at once up to six "high" (although there is some controversy as to whether this counts as the number of catches achieved is so small) and five "low". Most diaboloists, however, stick to using only two or three diabolos at once. The introduction of multiple diabolos on a single string allows for many new moves. Many are applications of one-diabolo moves to multiple diabolos. Vertax Another advanced diabolo style is vertax (vertical axis; also known as "Excalibur"). This is where the diabolo is "turned vertically" by means of "whipping" and is continually spun in this upright state. The person spinning it needs to rotate their body to keep up with the constant whipping action due to the momentum and centripetal motion at which the diabolo spins. Although the number of tricks seems limited, people are finding more ways to perform with this style, including vertax genocides, infinite suicides, and many suns, orbits, and satellites. It is also possible to have two diabolos in one string in vertax; this feat has been achieved by a small number of diaboloists. It has also been done in the form of a fan. Most of these tricks are accomplished by street performers in competitions, notably the GEDC and the Taipei PEC. Some cutting-edge skilled vertax jugglers include William (Wei-Liang) Lin (in 2006, ranked #1 in the world), Ryo Yabe (multiple diabolos), Higami (a Japanese juggling group, noted for inventing the first 'infinite suicide vertax'), and Jonathan P. Chen (noted for inventing the vertax genocide); these jugglers are former and multiple winners of the above-mentioned cups. Eric and Antonin (France) and Nate and Jacob Sharpe (USA) have contributed greatly to the development of vertax passing techniques. Finally, Alexis Levillon invented many vertax tricks including vertax integrals, furthered multidiabolo vertax, and has also invented the "Galexis" style, where one diabolo is horizontal, while the other is in vertax. Contact diabolo This is a relatively recent style of diabolo that is gaining popularity. It utilizes the diabolo so that it has little or no