Algorithmic Art

%show Renders the Sketch

The %show magic is the only way to display a sketch. When executed, it:

1. Bootstraps a fresh p5.js instance inside an iframe
2. Loads any ES module imports
3. Combines all registered code from previous cells (deduplicated)
4. Starts the p5 sketch (setup() then draw() loop)

Without %show, nothing is displayed — code cells only register definitions.

Live Updates

After a %show cell has been displayed, re-executing any code cell automatically updates all existing %show displays with the new code. This enables live tweaking of parameters and functions without re-running %show.

Global Mode

The kernel runs p5.js in global mode. All p5.js functions and constants are available as globals — no p5. prefix needed:

• Drawing: createCanvas, background, fill, stroke, noFill, noStroke, circle, rect, ellipse, line, point, triangle, quad, arc, beginShape, vertex, endShape
• Color: color, colorMode, lerpColor, red, green, blue, alpha, hue, saturation, brightness
• Math: random, noise, map, lerp, constrain, dist, abs, floor, ceil, round, sin, cos, atan2, pow, sqrt, log, exp, min, max
• Vectors: createVector, p5.Vector.fromAngle, p5.Vector.random2D
• Transform: translate, rotate, scale, push, pop, applyMatrix
• Constants: PI, TWO_PI, HALF_PI, QUARTER_PI, TAU, CENTER, CORNER, CORNERS, RADIUS, CLOSE
• System variables: width, height, mouseX, mouseY, pmouseX, pmouseY, frameCount, deltaTime, windowWidth, windowHeight, innerWidth, innerHeight
• Seeding: randomSeed, noiseSeed
• Control: noLoop, loop, frameRate, redraw
• Blend modes: blendMode, ADD, MULTIPLY, SCREEN, OVERLAY, DIFFERENCE

ES Module Imports

The kernel supports ES module imports from npm (auto-resolved via jsDelivr), GitHub, or direct URLs:

// npm package (default import)
import confetti from 'canvas-confetti';

// Named imports
import { shuffle, debounce } from 'lodash-es';

// Namespace import
import * as d3 from 'd3';

// From GitHub
import something from 'gh/user/repo/file.js';

// Direct URL
import lib from 'https://example.com/lib.js';

Imports are tracked across cells and included when %show generates the sketch.

Event Handlers

p5.js event handler functions can be defined in code cells and will be included in the sketch:

• Mouse: mousePressed(), mouseReleased(), mouseMoved(), mouseDragged(), mouseClicked(), doubleClicked(), mouseWheel()
• Keyboard: keyPressed(), keyReleased(), keyTyped()
• Window: windowResized()

p5.js Reference

When you need to look up specific p5.js functions, signatures, or behavior, consult the official documentation:

• Reference (API docs): https://p5js.org/reference/
• Examples: https://p5js.org/examples/
• Tutorials: https://p5js.org/tutorials/
• WebGL: https://github.com/processing/p5.js/wiki/Getting-started-with-WebGL-in-p5

The kernel also provides built-in documentation for p5.js functions via Shift+Tab inspect in the notebook.

Core Process

Phase 1: Algorithmic Philosophy

Before writing any code, develop a manifesto for a generative aesthetic movement. Write 4-6 paragraphs in a markdown cell covering:

• Movement name (1-2 words) as the cell heading
• A vision articulating the computational aesthetic — what mathematical relationships, emergent behaviors, and algorithmic processes define this movement
• The mechanisms at play: noise functions, particle systems, field dynamics, geometric transformations, or mathematical mappings
• Emphasis on craftsmanship: the algorithm should feel meticulously crafted, the product of deep computational expertise refined through countless iterations
• Creative space for interpretation during implementation

Key principle: "Beauty lives in the process, not the final frame." Each execution with a different seed reveals unique variations of the same algorithmic vision.

Phase 2: Notebook Expression

Implement the philosophy through notebook cells using the p5.js kernel.

Notebook Structure

Create a notebook (.ipynb) with the following cell structure:

Cell 1 — Title & Philosophy (Markdown)

# [Movement Name]

[4-6 paragraphs of algorithmic philosophy developed in Phase 1]

Cell 2 — Parameters & Configuration (Code)

Define all tunable parameters at the top so they are easy to adjust:

// Seed for reproducibility
let seed = 42;

// Parameters — tunable system properties
let params = {
  particleCount: 500,
  noiseScale: 0.005,
  flowSpeed: 2.0,
  trailLength: 50,
  colorShift: 0.3,
  decayRate: 0.95,
  angleOffset: PI / 6,
  threshold: 0.4
};

// Palette
let palette = ['#264653', '#2a9d8f', '#e9c46a', '#f4a261', '#e76f51'];

Cell 3+ — Helper Classes & Utilities (Code)

If the algorithm requires helper classes or utility functions, define them in intermediate cells before the main sketch:

class Particle {
  constructor(x, y) {
    this.pos = createVector(x, y);
    this.vel = createVector(0, 0);
    // ...
  }

  update() { /* ... */ }
  display() { /* ... */ }
}

Use markdown cells between code sections to explain the algorithmic approach when helpful.

Sketch Definition Cell — setup() and draw() (Code)

The main p5.js sketch with setup() and draw(). All parameters, classes, and helpers must be defined in earlier cells first.

function setup() {
  createCanvas(innerWidth, innerHeight);
  randomSeed(seed);
  noiseSeed(seed);
  // ... initialization using params, palette, and helper classes from earlier cells
}

function draw() {
  // ... generative algorithm
}

Final Cell — Display with %show (Code)

The %show magic is required to render the sketch. Without it, code cells only register definitions — nothing is displayed. This MUST be the last cell.

%show

%show accepts optional width and height arguments (defaults: 100% width, 400px height):

%show 100% 800

Technical Requirements

Seeded Randomness

Every sketch MUST use seeded randomness for reproducibility:

randomSeed(seed);
noiseSeed(seed);

Changing the seed should produce a distinct but aesthetically coherent variation.

Parameter Design

Design parameters around system qualities, not pattern types:

• Quantities: particle counts, layer counts, iteration counts
• Scales: noise scale, size multipliers, amplitude
• Probabilities: branching chance, mutation rate, spawn probability
• Ratios: aspect ratios, golden ratio subdivisions, density ratios
• Angles: rotation offsets, angular velocity, spiral tightness
• Thresholds: activation levels, distance cutoffs, opacity limits

Canvas & Rendering

• Use createCanvas(innerWidth, innerHeight) so the sketch fills the %show output iframe — this ensures proper rendering regardless of the display size
• Use background() in setup() for static compositions, or with low alpha in draw() for trail effects
• Prefer noStroke() with filled shapes, or thin strokes with noFill(), depending on the aesthetic
• Use blendMode() for layering effects when appropriate

Color

• Define palettes as arrays of hex strings or HSB values
• Use colorMode(HSB, 360, 100, 100, 100) for hue-based generative color
• Ensure visual harmony — colors should feel intentional, not random

Performance

• For particle systems, keep counts reasonable (100-2000 depending on complexity)
• Use noLoop() for static compositions that render once
• Avoid unnecessary per-frame allocations

Algorithmic Approaches

Choose approaches that serve the philosophy. Some possibilities:

• Flow fields: Perlin/simplex noise-driven vector fields guiding particles
• Recursive subdivision: Space partitioning with varying rules per depth
• L-systems / turtle graphics: Rule-based organic growth
• Voronoi / Delaunay: Tessellation-based compositions
• Attractors: Strange attractors (Lorenz, Clifford, De Jong) as compositional scaffolding
• Reaction-diffusion: Turing patterns and biological simulation
• Wave interference: Overlapping sinusoidal or circular wave patterns
• Stochastic geometry: Randomized geometric constructions with probabilistic rules

Craftsmanship Standards

• Avoid redundancy: Each algorithmic concept should appear once — do not repeat the same noise or particle logic in different forms
• Balance complexity and clarity: The code should be readable; the output should be visually rich
• Visual hierarchy: Even within randomness, there should be focal points, rhythm, and spatial balance
• Reproducibility: Same seed, same output — always
• Algorithmic essence over static composition: The beauty is in the process; each seed is a unique expression of the same underlying system

What NOT to Do

• Do not use external images or assets — everything is generated algorithmically
• Do not hardcode positions or shapes — let the algorithm determine composition
• Do not create static drawings — the system should be parameterized and seed-driven
• Do not over-comment the code — let the philosophy markdown cell and clean code speak for themselves
• Do not use mouseX/mouseY for the core composition — interactivity is optional and secondary to the algorithmic output
• Do not forget the %show cell — without it, the sketch will not render