My latest experiment sketch with p5.js involving work with arrays. You will probably need to click on the image to activate it. Use the “t”,”s” and “c” keys on your keyboard to add a triangle, square or circle to the scene (size and color are randomized).

The sketch can be viewed on a separate page here (which will probably perform at a faster frame rate), and the p5 source code is available here. Each shape is added as an independent object to the master shape array. The number of elements currently in the master array is displayed at the top left. As the shapes fall and are shuttled off to the left or right (again, a random choice), they are “spliced” from the array after they leave the screen, hence why the count goes down.
This sketch also makes use of the p5.scribble library, which gives the shapes their jagged, “sketchy” appearance. If you un-comment the “randomSeed” statement in line 15 of the code, this will stop the animation of the jagged-ness, since the randomization used for that effect (in the p5.scribble code) is then “seeded” continually with the same number. (This number could be anything…not just “98”.)