diff --git a/src/math/trigonometry.js b/src/math/trigonometry.js
index 4927bb8d2c..51f42d71a9 100644
--- a/src/math/trigonometry.js
+++ b/src/math/trigonometry.js
@@ -16,9 +16,11 @@ import * as constants from '../core/constants';
 p5.prototype._angleMode = constants.RADIANS;
 
 /**
- * The inverse of <a href="#/p5/cos">cos()</a>, returns the arc cosine of a
- * value. This function expects arguments in the range -1 to 1. By default,
- * `acos()` returns values in the range 0 to &pi; (about 3.14). If the
+ * Calculates the arc cosine of a number.
+ *
+ * `acos()` is the inverse of <a href="#/p5/cos">cos()</a>. It expects
+ * arguments in the range -1 to 1. By default, `acos()` returns values in the
+ * range 0 to &pi; (about 3.14). If the
  * <a href="#/p5/angleMode">angleMode()</a> is `DEGREES`, then values are
  * returned in the range 0 to 180.
  *
@@ -29,27 +31,45 @@ p5.prototype._angleMode = constants.RADIANS;
  * @example
  * <div>
  * <code>
- * let a = PI;
- * let c = cos(a);
- * let ac = acos(c);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(c, 3)}`, 35, 50);
- * text(`${round(ac, 3)}`, 35, 75);
- *
- * describe('The numbers 3.142, -1, and 3.142 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate cos() and acos() values.
+ *   let a = PI;
+ *   let c = cos(a);
+ *   let ac = acos(c);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(c, 3)}`, 35, 50);
+ *   text(`${round(ac, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 3.142, -1, and 3.142 written on separate rows.');
+ * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
- * let a = PI + QUARTER_PI;
- * let c = cos(a);
- * let ac = acos(c);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(c, 3)}`, 35, 50);
- * text(`${round(ac, 3)}`, 35, 75);
- *
- * describe('The numbers 3.927, -0.707, and 2.356 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate cos() and acos() values.
+ *   let a = PI + QUARTER_PI;
+ *   let c = cos(a);
+ *   let ac = acos(c);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(c, 3)}`, 35, 50);
+ *   text(`${round(ac, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 3.927, -0.707, and 2.356 written on separate rows.');
+ * }
  * </code>
  * </div>
  */
@@ -58,11 +78,12 @@ p5.prototype.acos = function(ratio) {
 };
 
 /**
- * The inverse of <a href="#/p5/sin">sin()</a>, returns the arc sine of a
- * value. This function expects input values in the range of -1 to 1. By
- * default, `asin()` returns values in the range -&pi; &divide; 2
- * (about -1.57) to &pi; &divide; 2 (about 1.57). If the
- * <a href="#/p5/angleMode">angleMode()</a> is `DEGREES` then values are
+ * Calculates the arc sine of a number.
+ *
+ * `asin()` is the inverse of <a href="#/p5/sin">sin()</a>. It expects input
+ * values in the range of -1 to 1. By default, `asin()` returns values in the
+ * range -&pi; &divide; 2 (about -1.57) to &pi; &divide; 2 (about 1.57). If
+ * the <a href="#/p5/angleMode">angleMode()</a> is `DEGREES` then values are
  * returned in the range -90 to 90.
  *
  * @method asin
@@ -72,27 +93,45 @@ p5.prototype.acos = function(ratio) {
  * @example
  * <div>
  * <code>
- * let a = PI / 3;
- * let s = sin(a);
- * let as = asin(s);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(s, 3)}`, 35, 50);
- * text(`${round(as, 3)}`, 35, 75);
- *
- * describe('The numbers 1.047, 0.866, and 1.047 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate sin() and asin() values.
+ *   let a = PI / 3;
+ *   let s = sin(a);
+ *   let as = asin(s);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(s, 3)}`, 35, 50);
+ *   text(`${round(as, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 1.047, 0.866, and 1.047 written on separate rows.');
+ * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
- * let a = PI + PI / 3;
- * let s = sin(a);
- * let as = asin(s);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(s, 3)}`, 35, 50);
- * text(`${round(as, 3)}`, 35, 75);
- *
- * describe('The numbers 4.189, -0.866, and -1.047 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate sin() and asin() values.
+ *   let a = PI + PI / 3;
+ *   let s = sin(a);
+ *   let as = asin(s);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(s, 3)}`, 35, 50);
+ *   text(`${round(as, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 4.189, -0.866, and -1.047 written on separate rows.');
+ * }
  * </code>
  * </div>
  */
@@ -101,12 +140,13 @@ p5.prototype.asin = function(ratio) {
 };
 
 /**
- * The inverse of <a href="#/p5/tan">tan()</a>, returns the arc tangent of a
- * value. This function expects input values in the range of -Infinity to
- * Infinity. By default, `atan()` returns values in the range -&pi; &divide; 2
- * (about -1.57) to &pi; &divide; 2 (about 1.57). If the
- * <a href="#/p5/angleMode">angleMode()</a> is `DEGREES` then values are
- * returned in the range -90 to 90.
+ * Calculates the arc tangent of a number.
+ *
+ * `atan()` is the inverse of <a href="#/p5/tan">tan()</a>. It expects input
+ * values in the range of -Infinity to Infinity. By default, `atan()` returns
+ * values in the range -&pi; &divide; 2 (about -1.57) to &pi; &divide; 2
+ * (about 1.57). If the <a href="#/p5/angleMode">angleMode()</a> is `DEGREES`
+ * then values are returned in the range -90 to 90.
  *
  * @method atan
  * @param  {Number} value value whose arc tangent is to be returned.
@@ -115,27 +155,45 @@ p5.prototype.asin = function(ratio) {
  * @example
  * <div>
  * <code>
- * let a = PI / 3;
- * let t = tan(a);
- * let at = atan(t);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(t, 3)}`, 35, 50);
- * text(`${round(at, 3)}`, 35, 75);
- *
- * describe('The numbers 1.047, 1.732, and 1.047 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate tan() and atan() values.
+ *   let a = PI / 3;
+ *   let t = tan(a);
+ *   let at = atan(t);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(t, 3)}`, 35, 50);
+ *   text(`${round(at, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 1.047, 1.732, and 1.047 written on separate rows.');
+ * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
- * let a = PI + PI / 3;
- * let t = tan(a);
- * let at = atan(t);
- * text(`${round(a, 3)}`, 35, 25);
- * text(`${round(t, 3)}`, 35, 50);
- * text(`${round(at, 3)}`, 35, 75);
- *
- * describe('The numbers 4.189, 1.732, and 1.047 written on separate rows.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Calculate tan() and atan() values.
+ *   let a = PI + PI / 3;
+ *   let t = tan(a);
+ *   let at = atan(t);
+ *
+ *   // Display the values.
+ *   text(`${round(a, 3)}`, 35, 25);
+ *   text(`${round(t, 3)}`, 35, 50);
+ *   text(`${round(at, 3)}`, 35, 75);
+ *
+ *   describe('The numbers 4.189, 1.732, and 1.047 written on separate rows.');
+ * }
  * </code>
  * </div>
  */
@@ -144,15 +202,17 @@ p5.prototype.atan = function(ratio) {
 };
 
 /**
- * Calculates the angle formed by a specified point, the origin, and the
- * positive x-axis. By default, `atan2()` returns values in the range
+ * Calculates the angle formed by a point, the origin, and the positive
+ * x-axis.
+ *
+ * `atan2()` is most often used for orienting geometry to the mouse's
+ * position, as in `atan2(mouseY, mouseX)`. The first parameter is the point's
+ * y-coordinate and the second parameter is its x-coordinate.
+ *
+ * By default, `atan2()` returns values in the range
  * -&pi; (about -3.14) to &pi; (3.14). If the
  * <a href="#/p5/angleMode">angleMode()</a> is `DEGREES`, then values are
- * returned in the range -180 to 180. The `atan2()` function is most often
- * used for orienting geometry to the mouse's position.
- *
- * Note: The y-coordinate of the point is the first parameter and the
- * x-coordinate is the second parameter.
+ * returned in the range -180 to 180.
  *
  * @method atan2
  * @param  {Number} y y-coordinate of the point.
@@ -162,17 +222,55 @@ p5.prototype.atan = function(ratio) {
  * @example
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   describe('A rectangle at the top-left of the canvas rotates with mouse movements.');
+ * }
+ *
  * function draw() {
  *   background(200);
- *   translate(width / 2, height / 2);
- *   let x = mouseX - width / 2;
- *   let y = mouseY - height / 2;
- *   let a = atan2(y, x);
+ *
+ *   // Calculate the angle between the mouse
+ *   // and the origin.
+ *   let a = atan2(mouseY, mouseX);
+ *
+ *   // Rotate.
  *   rotate(a);
- *   rect(-30, -5, 60, 10);
+ *
+ *   // Draw the shape.
+ *   rect(0, 0, 60, 10);
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
  *
  *   describe('A rectangle at the center of the canvas rotates with mouse movements.');
  * }
+ *
+ * function draw() {
+ *   background(200);
+ *
+ *   // Translate the origin to the center.
+ *   translate(50, 50);
+ *
+ *   // Get the mouse's coordinates relative to the origin.
+ *   let x = mouseX - 50;
+ *   let y = mouseY - 50;
+ *
+ *   // Calculate the angle between the mouse and the origin.
+ *   let a = atan2(y, x);
+ *
+ *   // Rotate.
+ *   rotate(a);
+ *
+ *   // Draw the shape.
+ *   rect(-30, -5, 60, 10);
+ * }
  * </code>
  * </div>
  */
@@ -181,10 +279,11 @@ p5.prototype.atan2 = function(y, x) {
 };
 
 /**
- * Calculates the cosine of an angle. `cos()` is useful for many geometric
- * tasks in creative coding. The values returned oscillate between -1 and 1
- * as the input angle increases. `cos()` takes into account the current
- * <a href="#/p5/angleMode">angleMode</a>.
+ * Calculates the cosine of an angle.
+ *
+ * `cos()` is useful for many geometric tasks in creative coding. The values
+ * returned oscillate between -1 and 1 as the input angle increases. `cos()`
+ * takes into account the current <a href="#/p5/angleMode">angleMode()</a>.
  *
  * @method cos
  * @param  {Number} angle the angle.
@@ -193,42 +292,65 @@ p5.prototype.atan2 = function(y, x) {
  * @example
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   describe('A white ball on a string oscillates left and right.');
+ * }
+ *
  * function draw() {
  *   background(200);
  *
- *   let t = frameCount;
- *   let x = 30 * cos(t * 0.05) + 50;
+ *   // Calculate the coordinates.
+ *   let x = 30 * cos(frameCount * 0.05) + 50;
  *   let y = 50;
+ *
+ *   // Draw the oscillator.
  *   line(50, y, x, y);
  *   circle(x, y, 20);
- *
- *   describe('A white ball on a string oscillates left and right.');
  * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   describe('A series of black dots form a wave pattern.');
+ * }
+ *
  * function draw() {
+ *   // Calculate the coordinates.
  *   let x = frameCount;
  *   let y = 30 * cos(x * 0.1) + 50;
- *   point(x, y);
  *
- *   describe('A series of black dots form a wave pattern.');
+ *   // Draw the point.
+ *   point(x, y);
  * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
- * function draw() {
- *   let t = frameCount;
- *   let x = 30 * cos(t * 0.1) + 50;
- *   let y = 10 * sin(t * 0.2) + 50;
- *   point(x, y);
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
  *
  *   describe('A series of black dots form an infinity symbol.');
  * }
+ *
+ * function draw() {
+ *   // Calculate the coordinates.
+ *   let x = 30 * cos(frameCount * 0.1) + 50;
+ *   let y = 10 * sin(frameCount * 0.2) + 50;
+ *
+ *   // Draw the point.
+ *   point(x, y);
+ * }
  * </code>
  * </div>
  */
@@ -237,10 +359,11 @@ p5.prototype.cos = function(angle) {
 };
 
 /**
- * Calculates the sine of an angle. `sin()` is useful for many geometric tasks
- * in creative coding. The values returned oscillate between -1 and 1 as the
- * input angle increases. `sin()` takes into account the current
- * <a href="#/p5/angleMode">angleMode</a>.
+ * Calculates the sine of an angle.
+ *
+ * `sin()` is useful for many geometric tasks in creative coding. The values
+ * returned oscillate between -1 and 1 as the input angle increases. `sin()`
+ * takes into account the current <a href="#/p5/angleMode">angleMode()</a>.
  *
  * @method sin
  * @param  {Number} angle the angle.
@@ -249,42 +372,65 @@ p5.prototype.cos = function(angle) {
  * @example
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   describe('A white ball on a string oscillates up and down.');
+ * }
+ *
  * function draw() {
  *   background(200);
  *
- *   let t = frameCount;
+ *   // Calculate the coordinates.
  *   let x = 50;
- *   let y = 30 * sin(t * 0.05) + 50;
- *   line(x, 50, x, y);
- *   circle(x, y, 20);
+ *   let y = 30 * sin(frameCount * 0.05) + 50;
  *
- *   describe('A white ball on a string oscillates up and down.');
+ *   // Draw the oscillator.
+ *   line(50, y, x, y);
+ *   circle(x, y, 20);
  * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   describe('A series of black dots form a wave pattern.');
+ * }
+ *
  * function draw() {
+ *   // Calculate the coordinates.
  *   let x = frameCount;
  *   let y = 30 * sin(x * 0.1) + 50;
- *   point(x, y);
  *
- *   describe('A series of black dots form a wave pattern.');
+ *   // Draw the point.
+ *   point(x, y);
  * }
  * </code>
  * </div>
  *
  * <div>
  * <code>
- * function draw() {
- *   let t = frameCount;
- *   let x = 30 * cos(t * 0.1) + 50;
- *   let y = 10 * sin(t * 0.2) + 50;
- *   point(x, y);
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
  *
  *   describe('A series of black dots form an infinity symbol.');
  * }
+ *
+ * function draw() {
+ *   // Calculate the coordinates.
+ *   let x = 30 * cos(frameCount * 0.1) + 50;
+ *   let y = 10 * sin(frameCount * 0.2) + 50;
+ *
+ *   // Draw the point.
+ *   point(x, y);
+ * }
  * </code>
  * </div>
  */
@@ -293,10 +439,12 @@ p5.prototype.sin = function(angle) {
 };
 
 /**
- * Calculates the tangent of an angle. `tan()` is useful for many geometric
- * tasks in creative coding. The values returned range from -Infinity
- * to Infinity and repeat periodically as the input angle increases. `tan()`
- * takes into account the current <a href="#/p5/angleMode">angleMode</a>.
+ * Calculates the tangent of an angle.
+ *
+ * `tan()` is useful for many geometric tasks in creative coding. The values
+ * returned range from -Infinity to Infinity and repeat periodically as the
+ * input angle increases. `tan()` takes into account the current
+ * <a href="#/p5/angleMode">angleMode()</a>.
  *
  * @method tan
  * @param  {Number} angle the angle.
@@ -305,12 +453,21 @@ p5.prototype.sin = function(angle) {
  * @example
  * <div>
  * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   describe('A series of identical curves drawn with black dots. Each curve starts from the top of the canvas, continues down at a slight angle, flattens out at the middle of the canvas, then continues to the bottom.');
+ * }
+ *
  * function draw() {
+ *   // Calculate the coordinates.
  *   let x = frameCount;
  *   let y = 5 * tan(x * 0.1) + 50;
- *   point(x, y);
  *
- *   describe('A series of identical curves drawn with black dots. Each curve starts from the top of the canvas, continues down at a slight angle, flattens out at the middle of the canvas, then continues to the bottom.');
+ *   // Draw the point.
+ *   point(x, y);
  * }
  * </code>
  * </div>
@@ -320,12 +477,14 @@ p5.prototype.tan = function(angle) {
 };
 
 /**
- * Converts an angle measurement in radians to its corresponding value in
- * degrees. Degrees and radians are two ways of measuring the same thing.
- * There are 360 degrees in a circle and 2 &times; &pi; (about 6.28)
- * radians in a circle. For example, 90° = &pi; &divide; 2 (about 1.57)
- * radians. This function doesn't take into account the current
- * <a href="#/p5/angleMode">angleMode()</a>.
+ * Converts an angle measured in radians to its value in degrees.
+ *
+ * Degrees and radians are both units for measuring angles. There are 360˚ in
+ * one full rotation. A full rotation is 2 &times; &pi; (about 6.28) radians.
+ *
+ * The same angle can be expressed in with either unit. For example, 90° is a
+ * quarter of a full rotation. The same angle is 2 &times; &pi; &divide; 4
+ * (about 1.57) radians.
  *
  * @method degrees
  * @param  {Number} radians radians value to convert to degrees.
@@ -334,23 +493,34 @@ p5.prototype.tan = function(angle) {
  * @example
  * <div>
  * <code>
- * let rad = QUARTER_PI;
- * let deg = degrees(rad);
- * text(`${round(rad, 2)} rad = ${deg}˚`, 10, 50);
+ * function setup() {
+ *   createCanvas(100, 100);
  *
- * describe('The text "0.79 rad = 45˚".');
+ *   background(200);
+ *
+ *   // Calculate the angle conversion.
+ *   let rad = QUARTER_PI;
+ *   let deg = degrees(rad);
+ *
+ *   // Display the conversion.
+ *   text(`${round(rad, 2)} rad = ${deg}˚`, 10, 50);
+ *
+ *   describe('The text "0.79 rad = 45˚".');
+ * }
  * </code>
  * </div>
  */
 p5.prototype.degrees = angle => angle * constants.RAD_TO_DEG;
 
 /**
- * Converts an angle measurement in degrees to its corresponding value in
- * radians. Degrees and radians are two ways of measuring the same thing.
- * There are 360 degrees in a circle and 2 &times; &pi; (about 6.28)
- * radians in a circle. For example, 90° = &pi; &divide; 2 (about 1.57)
- * radians. This function doesn't take into account the current
- * <a href="#/p5/angleMode">angleMode()</a>.
+ * Converts an angle measured in degrees to its value in radians.
+ *
+ * Degrees and radians are both units for measuring angles. There are 360˚ in
+ * one full rotation. A full rotation is 2 &times; &pi; (about 6.28) radians.
+ *
+ * The same angle can be expressed in with either unit. For example, 90° is a
+ * quarter of a full rotation. The same angle is 2 &times; &pi; &divide; 4
+ * (about 1.57) radians.
  *
  * @method radians
  * @param  {Number} degrees degree value to convert to radians.
@@ -359,44 +529,210 @@ p5.prototype.degrees = angle => angle * constants.RAD_TO_DEG;
  * @example
  * <div>
  * <code>
- * let deg = 45;
- * let rad = radians(deg);
- * text(`${deg}˚ = ${round(rad, 3)} rad`, 10, 50);
+ * function setup() {
+ *   createCanvas(100, 100);
  *
- * describe('The text "45˚ = 0.785 rad".');
+ *   background(200);
+ *
+ *   // Caclulate the angle conversion.
+ *   let deg = 45;
+ *   let rad = radians(deg);
+ *
+ *   // Display the angle conversion.
+ *   text(`${deg}˚ = ${round(rad, 3)} rad`, 10, 50);
+ *
+ *   describe('The text "45˚ = 0.785 rad".');
+ * }
  * </code>
  * </div>
  */
 p5.prototype.radians = angle => angle * constants.DEG_TO_RAD;
 
 /**
- * Changes the way trigonometric functions interpret angle values. By default,
- * the mode is `RADIANS`.
+ * Changes the unit system used to measure angles.
+ *
+ * Degrees and radians are both units for measuring angles. There are 360˚ in
+ * one full rotation. A full rotation is 2 &times; &pi; (about 6.28) radians.
+ *
+ * Functions such as <a href="#/p5/rotate">rotate()</a> and
+ * <a href="#/p5/sin">sin()</a> expect angles measured radians by default.
+ * Calling `angleMode(DEGREES)` switches to degrees. Calling
+ * `angleMode(RADIANS)` switches back to radians.
+ *
+ * Calling `angleMode()` with no arguments returns current angle mode, which
+ * is either `RADIANS` or `DEGREES`.
  *
- * Calling `angleMode()` with no arguments returns current angle mode.
  * @method angleMode
  * @param {Constant} mode either RADIANS or DEGREES.
+ *
  * @example
  * <div>
  * <code>
- * let r = 40;
- * push();
- * rotate(PI / 6);
- * line(0, 0, r, 0);
- * text('0.524 rad', r, 0);
- * pop();
- *
- * angleMode(DEGREES);
- * push();
- * rotate(60);
- * line(0, 0, r, 0);
- * text('60˚', r, 0);
- * pop();
- *
- * describe('Two diagonal lines radiating from the top left corner of a square. The lines are oriented 30 degrees from the edges of the square and 30 degrees apart from each other.');
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Rotate 1/8 turn.
+ *   rotate(QUARTER_PI);
+ *
+ *   // Draw a line.
+ *   line(0, 0, 80, 0);
+ *
+ *   describe('A diagonal line radiating from the top-left corner of a square.');
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Use degrees.
+ *   angleMode(DEGREES);
+ *
+ *   // Rotate 1/8 turn.
+ *   rotate(45);
+ *
+ *   // Draw a line.
+ *   line(0, 0, 80, 0);
+ *
+ *   describe('A diagonal line radiating from the top-left corner of a square.');
+ * }
  * </code>
  * </div>
  *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(50);
+ *
+ *   // Calculate the angle to rotate.
+ *   let angle = TWO_PI / 7;
+ *
+ *   // Move the origin to the center.
+ *   translate(50, 50);
+ *
+ *   // Style the flower.
+ *   noStroke();
+ *   fill(255, 50);
+ *
+ *   // Draw the flower.
+ *   for (let i = 0; i < 7; i += 1) {
+ *     ellipse(0, 0, 80, 20);
+ *     rotate(angle);
+ *   }
+ *
+ *   describe('A translucent white flower on a dark background.');
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(50);
+ *
+ *   // Use degrees.
+ *   angleMode(DEGREES);
+ *
+ *   // Calculate the angle to rotate.
+ *   let angle = 360 / 7;
+ *
+ *   // Move the origin to the center.
+ *   translate(50, 50);
+ *
+ *   // Style the flower.
+ *   noStroke();
+ *   fill(255, 50);
+ *
+ *   // Draw the flower.
+ *   for (let i = 0; i < 7; i += 1) {
+ *     ellipse(0, 0, 80, 20);
+ *     rotate(angle);
+ *   }
+ *
+ *   describe('A translucent white flower on a dark background.');
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   describe('A white ball on a string oscillates left and right.');
+ * }
+ *
+ * function draw() {
+ *   background(200);
+ *
+ *   // Calculate the coordinates.
+ *   let x = 30 * cos(frameCount * 0.05) + 50;
+ *   let y = 50;
+ *
+ *   // Draw the oscillator.
+ *   line(50, y, x, y);
+ *   circle(x, y, 20);
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   // Use degrees.
+ *   angleMode(DEGREES);
+ *
+ *   describe('A white ball on a string oscillates left and right.');
+ * }
+ *
+ * function draw() {
+ *   background(200);
+ *
+ *   // Calculate the coordinates.
+ *   let x = 30 * cos(frameCount * 2.86) + 50;
+ *   let y = 50;
+ *
+ *   // Draw the oscillator.
+ *   line(50, y, x, y);
+ *   circle(x, y, 20);
+ * }
+ * </code>
+ * </div>
+ *
+ * <div>
+ * <code>
+ * function setup() {
+ *   createCanvas(100, 100);
+ *
+ *   background(200);
+ *
+ *   // Draw the upper line.
+ *   rotate(PI / 6);
+ *   line(0, 0, 80, 0);
+ *
+ *   // Use degrees.
+ *   angleMode(DEGREES);
+ *
+ *   // Draw the lower line.
+ *   rotate(30);
+ *   line(0, 0, 80, 0);
+ *
+ *   describe('Two diagonal lines radiating from the top-left corner of a square. The lines are oriented 30 degrees from the edges of the square and 30 degrees apart from each other.');
+ * }
+ * </code>
+ * </div>
  */
 /**
  * @method angleMode