Pamela introduces arrays, a nifty way to store a sequence of multiple values in one variable.

Pamela introduces objects, a way to store a bag of properties in a single variable.

Jessica Liu explains how to use variables to hold on to a value to use later. Variables are an important part of programming, so pay close attention!

Was da Vinci an artistic genius? Sure, but he was also born in the right place at the right time -- pre-Renaissance, Western artists got little individual credit for their work. And in many non-Western cultures, traditional forms have always been prized over innovation. So, where do we get our notions of art vs. craft? Laura Morelli traces the history of how we assign value to the visual arts. Lesson by Laura Morelli, animation by Sandro Katamashvili.

Watch Jannis Kounellis combine painting music and dance. To learn more about what artists have to say, take our online course, Modern and Contemporary Art, 1945-1989. Created by The Museum of Modern Art.

An overview of joining tables to themselves with self-joins

Video by Art21. Episode #252: Shown working on two site-specific paintings for the San Francisco Museum of Modern Art (SFMOMA), Julie Mehretu recontextualizes the history of American landscape painting by merging its sublime imagery with the harsh realities not depicted. "What does it mean to paint a landscape and be an artist in this political moment?" she asks from the decommissioned Harlem church used as her studio for the project. Referencing the ways that landscapes have been politicized through historical events—from the violent expansion of the American West, colonialism, war, and abolition, through to more recent race riots and social protests—Mehretu began by combining photographs from these events with nineteenth-century landscape paintings. Abstracting and digitizing the blended forms, she printed the resulting images on two monumental canvases, each spanning more than eight hundred square feet. Over these underpaintings, Mehretu adds gestural, calligraphic brush strokes before screen printing an additional, complicating layer of pixelated images. Collaborator Jason Moran, a composer and jazz pianist, joins Mehretu in the studio to create a musical arrangement inspired by her improvisational process of markings and erasure. Through their respective practices, the two artists create new visual and auditory languages in the hopes of processing the complex history that brought us to our present moment. As Mehretu explains, the paintings become "visual neologisms," that combine the work and inventions of past artists, "to address when language isn't enough."

Primer on the differences of language and religion that helped to propel World War I. Created by Sal Khan.

In the year 1863, US General Ulysses S. Grant succeeds in securing the western theatre of war and moves east to take on Robert E. Lee.