Walking (also known as ambulation) is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step. This applies regardless of the number of limbs - even arthropods with six, eight or more limbs.

The word walk is descended from the Old English wealcan "to roll". In humans and other bipeds, walking is generally distinguished from running in that only one foot at a time leaves contact with the ground and there is a period of double-support. In contrast, running begins when both feet are off the ground with each step. This distinction has the status of a formal requirement in competitive walking events. For quadrupedal species, there are numerous gaits which may be termed walking or running, and distinctions based upon the presence or absence of a suspended phase or the number of feet in contact any time do not yield mechanically correct classification. The most effective method to distinguish walking from running is to measure the height of a person's center of mass using motion capture or a force plate at midstance. During walking, the center of mass reaches a maximum height at midstance while during running, it is at a minimum. Definitions based on the percent of the stride during which a foot is in contact with the ground (averaged across all feet) of greater than 50% contact corresponds well with identification of 'inverted pendulum' mechanics and are indicative of walking for animals with any number of limbs, although this definition is incomplete. Running humans and animals may have contact periods greater than 50% of a gait cycle when rounding corners, running uphill or carrying loads.

Nate Butler (born 1981) is an established songwriter, music producer, vocal producer and recording artist based in Atlanta, Georgia. He has been a part of 45 million records sold worldwide. Butler has worked with multi-platinum artists such as Luther Vandross,Victoria Beckham aka Posh Spice, Houston,Craig David,Backstreet Boys,3LW, Christina Milian, Stacie Orrico,JoJo, Aaron Carter, The Cheetah Girls and others. Butler launched the career of the platinum R&B group 3LW by writing their hit singles: No More (Baby I'ma Do Right) and Playas Gon' Play. Two of the members of 3LW, Kiely Williams and Adrienne Bailon went on to become members of the worldwide Disney sensation The Cheetah Girls. Butler also penned the notable chart topping R&B smash single "Afterparty" by Koffee Brown, also referred to as a R&B classic .

Butler's creative talents are just beginning to be heard as he continues to launch the careers of many artists, such as the American Idols and many overseas superstars who sell millions, such as S Club 7 (England), L5 (band) (France), Blue (boy band) (England), Sugababes (England), Miss3 (Norway), BoA (Japan), and Lola (Italy). Butler has racked up credits on blockbuster films such as Barbershop, Four Brothers,Dr. Dolittle 2,Save the Last Dance, and the Nickelodeon hit Jimmy Neutron.

Ludovico Einaudi OMRI (Italian pronunciation: [ludoˈviːko eiˈnaudi]) (born 23 November 1955 in Turin, Piedmont) is an Italian pianist and composer.

Einaudi was born in Turin, Italy. His mother played to him on the piano as a child. He began his musical training at the Conservatorio Verdi in Milan, gaining a diploma in composition in 1982. That same year, he studied with Luciano Berio and gained a scholarship to the Tanglewood Music Festival.

After studying at the Conservatory in Milan, and subsequently with Berio, he spent several years composing in traditional forms. In the mid-1980s he began to search for a more personal expression in a series of works for dance and multimedia, and later for piano. His music is ambient, meditative and often introspective, drawing on minimalism, world music, and contemporary pop. He has made a significant impact in the film world, with four international awards to his name.^{[citation needed]}

His father, Giulio Einaudi, was a publisher, and his grandfather, Luigi Einaudi, was President of Italy between 1948 and 1955. He currently resides on a vineyard in the Italian region of Piedmont.