The rect() function is an inbuilt function in p5.js which is used to draw the rectangle on the screen. A rectangle contains four sides and four angles. Each angle of the rectangle is 90 degree. The length of the opposite sides of rectangles are equal. 
 
Syntax:
rect( x, y, w, h, tl, tr, br, bl )
or 
 
rect( x, y, w, h, detailX, detailY )
Parameters: This function accepts many parameters as mentioned above and described below:
- x: It is used to set the x-coordinate of rectangle.
 - y: It is used to set the y-coordinate of rectangle.
 - w: It is used to set the width of rectangle.
 - h: It is used to set the height of rectangle.
 - tl: It is optional parameter and used to set the radius of top-left corner.
 - tr: It is optional parameter and used to set the radius of top-right corner.
 - br: It is optional parameter and used to set the radius of bottom-right corner.
 - bl: It is optional parameter and used to set the radius of bottom-left corner.
 - detailX: It is used to set the number of segment in x-direction.
 - detailY: It is used to set the number of segment in y-direction.
 
Example 1:
javascript
function setup() {             // Create Canvas of given size      createCanvas(400, 300);     }     function draw() {             background(220);            // Use color() function     let c = color('green');        // Use fill() function to fill color     fill(c);          // Draw a rectangle     rect(50, 50, 300, 200);      }   | 
Output: 
 
Example 2:
javascript
function setup() {             // Create Canvas of given size      createCanvas(400, 300);     }     function draw() {             background(220);            // Use color() function     let c = color('green');        // Use fill() function to fill color     fill(c);          // Draw a rectangle     rect(50, 50, 300, 200, 30);      }   | 
Output: 
 
Example 3:
javascript
function setup() {             // Create Canvas of given size      createCanvas(400, 300);     }     function draw() {             background(220);            // Use color() function     let c = color('green');        // Use fill() function to fill color     fill(c);          // Draw a rectangle      rect(50, 50, 300, 200, 10, 20, 30, 40);      }   | 
Output: 
 
Online editor: https://editor.p5js.org/ 
Environment Setup: https://www.geeksforgeeks.org/p5-js-soundfile-object-installation-and-methods/
Reference: https://p5js.org/reference/#/p5/rect

                                    