1. Line

2. A line is an identifiable path created by a point moving in space
A line is an identifiable path created by a point moving in space. It is one-dimensional and can vary in width, direction, and length. Lines often define the edges of a form. Lines can be horizontal, vertical, or diagonal, straight or curved, thick or thin. They lead your eye around the composition and can communicate information through their character and direction.

3. Horizontal
In the late 1640s and early 1650s, at the height of his artistic maturity, Nicolas Poussin turned from historical narrative to landscape painting. Landscape with a Calm does not illustrate a story but rather evokes a mood. The ordered composition and clear, golden light contribute to A Calm's utter tranquility, while glowing, gem-like colors and fluid paint strokes enliven this scene of benevolent nature. Poussin's sketching campaigns in the Roman countryside with his friend and fellow landscape painter Claude Lorrain account, in part, for its fresh observation of cloud-scattered sky and grazing goats.  Poussin painted a pendant to this painting, Landscape with a Storm, now in a museum in Rouen. Together their contrasting weather effects embody nature's changing and unpredictable relationship with man. Poussin painted these works for the Parisian merchant Jean Pointel, a friend a great collector of his landscape paintings. 
Nicolas Poussin  French,   Landscape with a Calm Oil on canvas  38 3/16 x 51 9/16 in.  Getty Museum 97.PA.60

4. Vertical
Lines often communicate a sense of height because they are perpendicular to the earth, extending upwards toward the sky. In this church interior, vertical lines suggest spirituality, rising beyond human reach toward the heavens.
In preparation for one of his scrupulously observed paintings of buildings, Pieter Saenredam, known to his contemporaries as the "first portraitist of architecture," made this drawing as the second of two preliminary studies of the choir and north ambulatory of Saint Bavo. He first produced a perspective rendering in October 1634, working on location inside the church. In his studio a month later, Saenredam transformed the life study into this finely tuned, idealized drawing showing the deep vista from one of the side chapels across the nave to another. According to the inscription, he completed his painting after this drawing on October 15, 1635.  Saenredam began the drawing with a series of vertical and horizontal ruled graphite lines that delineate the faces of the side piers and establish a central vanishing point, clearly visible between the figures in the lower center. He then elaborately finished the sheet in pen and ink, wash, and watercolor. Corrections made during this phase included removing two figures from in front of the columns. 
Pieter Jansz. Saenredam   The Choir and North Ambulatory of the Church of Saint Bavo, Haarlem Dutch, November 1634   Pen and brown ink and watercolor, stylus incising throughout; verso rubbed with black chalk for transfer to panel  14 13/16 x 15 7/16 in.  88.GC.131 

5. Horizontal and vertical lines
used in combination communicate stability and solidity. Rectilinear forms with 90-degree angles are structurally stable. This stability suggests permanence and reliability
Northern European tourists and collectors in the 1600s and 1700s eagerly acquired pietre dure (hardstone) plaques and mosaic scenes produced by Roman craftsmen on trips to Italy. When the travelers returned home, they had these souvenirs mounted onto boxes and furniture.  The hardstone plaques on this pair of cabinets all date from the late 1600s; they were probably made by Italian craftsmen working in Paris at the Gobelins Manufactory. Because of their value and continued popularity with collectors, these plaques were mounted in cabinets specially designed to hold them, nearly one hundred years after their creation.  The catalogues of two sales held during the French Revolution describe this cabinet. William Beckford, a wealthy English connoisseur of hardstones, probably purchased it in the late 1700s. He may have ordered another cabinet made to match it, with identical gilt bronze mounts and dimensions
Attributed to Adam Weisweiler  One of a pair of cabinets French, Paris, about 1810  Oak veneered with ebony and pewter; set with pietre dure plaques; gilt bronze mounts; portor d'Italie marble tops  H: 3 ft. 4 in. x W: 4 ft. 11 1/8 in. x D: 1 ft. 8 7/8 in.  76.DA.9.1

6. Diagonal lines
convey a feeling of movement. Objects in a diagonal position are unstable. Because they are neither vertical nor horizontal, they are either about to fall or are already in motion. The angles of the ship and the rocks on the shore convey a feeling of movement or speed in this stormy harbor scene.
Claude-Joseph Vernet depicted a storm's aftermath: dark clouds above an angry sea, a shipwrecked boat and its anxious survivors, and listing ships in the distance. As the sea furiously beats against the shoreline, waves explode beyond the rocks in a froth of white. The motion of the waves, the distant rain shaft, the battered ship, and even the bodies of the fleeing castaways fill the scene with strong, opposing diagonal lines. The lighthouse standing solidly upright at the painting's center counters all of this activity.  The strong colors of the shipwrecked survivors' clothing stand out against the paletteof greens, grays, and browns in the turbulent sea. Clearing skies cast the survivors in an eerie glow; dark tones at the left and lower edges and in the waves themselves draw further attention to the bright figures.  The scene as a whole suggests the powerful force of nature over man. Vernet's companion piece for this painting, A Calm at a Mediterranean Port, presents a sharply contrasting scene of a harbor in more placid weather. 
Claude-Joseph Vernet  A Storm on a Mediterranean Coast French, Paris, 1767  Oil on canvas  44 1/2 x 57 3/8 in. 

7. Attributed to Silas A. Holmes St. Paul's Chapel
Diagonal lines .
In a two-dimensional composition, diagonal lines can also indicate depth through perspective. These diagonal lines pull the viewer visually into the image. For example, in this photograph the diagonal lines lead the eye into the space to the point where the lines converge.
There is little in this image to indicate that residential neighborhood along New York's Fifth Avenue would become a well-known center of commercial activity. Rows of single-family brownstones with grand front stoops line the wide corridor. While children play on the broad sidewalk and carriages make deliveries, a group of girls stand on the small balcony of the corner house. In the distance, the 1854 steeple of Marble Collegiate Church at 29th Street punctuates the rows of recently built homes and newly planted trees
Attributed to Silas A. Holmes  St. Paul's Chapel
American, New York City, about 1855  Salt print  10 x 14 13/16 in.  84.XM.351.5

8. Curved lines
can convey energy. Soft, shallow curves recall the curves of the human body and often have a pleasing, sensual quality and a softening effect on the composition. The edge of the pool in this photograph gently leads the eye to the sculptures on the horizon.
Sharply curved or twisted lines can convey turmoil, chaos, and even violence. In this sculpture, the lines of the contorting bodies and the serpent help convey the intensity of the struggle against the snake's stranglehold. can convey energy. Soft, shallow curves recall the curves of the human body and often have a pleasing, sensual quality and a softening effect on the composition.
By composing this picture with the pool in the foreground, Eugène Atget created a dynamic composition that incorporates the sweeping horizontal curve of the pool's edge as well as the receding line of the trees. The pool and gardens at Saint-Cloud were originally designed for Louis XIV's brother, the Duc d'Orléans, whose landscape architect contrived remarkable perspectives by employing optical illusions. To create the effect of great distance, progressively smaller greenery recedes along the alley behind the pool. Although the royal château that once occupied these grounds burned in 1870 during the Franco-Prussian war, the gardens survived untouched.
Eugène Atget  Pool, Saint-Cloud French, Saint-Cloud, about   Albumen print 7 3/16 x 8 9/16 in.  90.XM.64.51

9. Curved lines
Sharply curved or twisted lines can convey turmoil, chaos, and even violence. In this sculpture, the lines of the contorting bodies and the serpent help convey the intensity of the struggle against the snake's stranglehold. can convey energy. Soft, shallow curves recall the curves of the human body and often have a pleasing, sensual quality and a softening effect on the composition.
Laocoön and his two sons writhe and struggle, caught in the grip of the serpents that wind among their limbs. The father's large size, powerful musculature, and wild hair and beard contrast with his smaller, smoother-limbed sons. As retold in Greek mythology, the Trojan prince Laocoön angered Apollo by breaking a vow of celibacy he swore to the god and then warning the Trojans not to bring the wooden horse left by the Greeks into the city. To silence him, Apollo sent serpents from the sea to kill him and his sons.  Giovanni Battista Foggini's bronze of this story is based on a famous marble sculpture of the Laocoön unearthed in Rome in The Roman historian Pliny had described this renowned sculpture in awed language, as "a work to be preferred to all that the arts of painting and sculpture have produced." Its celebrity prompted many bronze reductions, or smaller-scale copies including this one, made in Florence. Although it imitates an antique work, the emotionalism and frontality of this bronze are characteristics of the late Baroque Florentine style.  This type of tabletop bronze was often displayed on a cabinet where it served as a souvenir of the "Grand Tour," evidence of its owner's classical education. 
Giovanni Battista Foggini  Italian, Florence, about 1720  Bronze  H: 22 1/16 x W: 17 5/16 x D: 8 5/8 in. 

10. Lines > Pattern
When repeated, lines can create a pattern. In this example, the artist repeated different kinds of lines across the composition to create various patterns. Patterned lines also give the image rhythm.
Vincent van Gogh made this drawing in varied hues of golden brown ink as a study of a painting. The vertical composition, whereby forms grow smaller and denser as the eye moves up, leads the eye across the stubble of a newly cut wheat field framed by gathered stacks of wheat. In the center, a man scythes a section of the field while a woman bundles cut wheat under her arm. The background shifts to the cityscape of Arles, where churches and densely packed houses stretch across the horizon. A railroad train and factories churning smoke into the sky signal the dawn of the machine world and its effect on traditional ways of life.  This drawing embodies many of the characteristic features of van Gogh's work: remarkably varied graphic strokes, a subject matter that comments on the human condition, a golden glow that suggests the warm light of southern France, and a balanced yet dynamic composition.
Vincent van Gogh  Arles: View from the Wheatfields Dutch, France, 1888  Reed and quill pens and brown ink 12 5/8 x 9 5/8 in. 

11. Vincent van Gogh Dutch, 1853-1890X
Vincent van Gogh Dutch,
Cottages with a Woman Working in the Middle Ground, 1890 Weeping Tree, 1889 Art Institute of Chicago

12. Rembrandt Three Trees

13. Vincent van Gogh Dutch, 1853-1890 Tetards (Pollards), 1884 X
Vincent van Gogh Dutch,
Tetards (Pollards), 1884
Weeping Tree, 1889 Art Institute of Chicago

14. Vincent van Gogh Dutch, 1853-1890 Weeping Tree, 1889 Art Institute of Chicago

15. Wheat Field with Cypresses at the Haude Galline near Eygalieres
Vincent van Gogh - 1889  Drawing Height: 47 cm (18.5 in.), Width: 62 cm (24.41 in.)  Van Gogh Museum (Netherlands) 

16. Vincent van Gogh Dutch, 1853-1890 Cypresses, 1889 Art Institute of Chicago

17. Elizabeth Catlett. American, born 1915
Sharecropper, 1952, printed 1970
Color linocut on cream Japanese paper 450 x 431 mm (block); 544 x 513 mm (sheet) Signed recto, lower right: "Elizabeth Catlett"; inscribed recto, lower left: "A/P Sharecropper" Restricted gift of Mr. and Mrs. Robert S. Hartman,
© Elizabeth Catlett/Licensed by VAGA, New York, NY. Art Institute of Chicago

18. Larry Rivers Portrait of Edwin Denby, 1953 Pencil on paper 16 3/8 x 19 3/4" (41.5 x 50.1 cm) The MUseum of Modern Art, New York City

19. William Kentridge  Learning the Flute  Courtesy Museum of Modern Art New York © 2010 William Kentridge

20. William Kentridge  Learning the Flute  Courtesy Museum of Modern Art New York © 2010 William Kentridge

21. William Kentridge  Seated Couple (Back to Back) 1998 Courtesy Museum of Modern Art New York © 2010 William Kentridge

22. Robert Longo, Untitled, from Men in the Cities , 1981-87
Robert Longo, Untitled, from Men in the Cities , Charcoal, graphite, and ink on paper, 96 x 48 inches/238.8 x cm. Private Collection

23. Robert Longo, UUNTITLED (HELL'S GATE) 2001 Charcoal on mounted paper
69 x 72 inches/175.3 x cm

24. Pablo Picasso, Portrait of Olga in a fur collar, 1923.

25. Pablo Picasso, Head of Marie Therese, 1933