Agent Skills: Cascading appear

When to use

Use this skill when creating mathematical animations, visualizations, or educational videos using Manim (ManimCE).

Quick Reference (Core Patterns)

Colors

BG = "#1c1c1c"           # Background (MUST use)
BLUE = "#3b82f6"         # Primary, nodes
YELLOW = "#fbbf24"       # Highlights, emphasis
GREEN = "#22c55e"        # Success, done, positive
RED = "#ef4444"          # Error, negative
GRAY = "#9ca3af"         # Inactive, labels

Scene Template

from manim import *

class MyScene(Scene):
    def construct(self):
        self.camera.background_color = "#1c1c1c"
        # Your code here
        self.wait(2)  # End padding

Audio-Synced Scene (StrictSync)

TIMING = {
    "01": {"start": 0, "end": 5.5},
    "02": {"start": 5.5, "end": 10.0},
}

class SyncedScene(Scene):
    def construct(self):
        self.camera.background_color = "#1c1c1c"
        for seg_id in sorted(TIMING.keys()):
            method = getattr(self, f"seg_{seg_id}", None)
            if method:
                self._run(seg_id, method)
        self.wait(2)

    def _run(self, seg_id, method):
        t = TIMING[seg_id]
        target = t["end"] - t["start"]
        start = self.renderer.time
        method()
        elapsed = self.renderer.time - start
        if elapsed < target:
            self.wait(target - elapsed)

    def seg_01(self):
        pass  # Your animation

Animation Patterns

# Cascading appear
self.play(LaggedStartMap(FadeIn, VGroup(*items), lag_ratio=0.15), run_time=1)

# Highlight
self.play(Flash(mob, color=YELLOW, line_length=0.2), run_time=0.3)
self.play(Indicate(mob, color=YELLOW), run_time=0.5)

# Transform text
self.play(TransformMatchingStrings(old_text, new_text), run_time=0.5)

# Coordinated (not sequential)
self.play(FadeIn(a), Create(b), Write(c), run_time=1)  # Good
# self.play(FadeIn(a)); self.play(Create(b))  # Bad

Layout

# Screen zones
title.to_edge(UP, buff=0.5)
content.move_to(ORIGIN)
info.to_edge(DOWN, buff=0.8)
sidebar.to_edge(RIGHT, buff=1.0)

# Spacing constants
NODE_GAP = 1.5        # Minimum between nodes
EDGE_LABEL_OFFSET = 0.22  # Perpendicular to edge

# Edge label placement
mid = line.get_center()
direction = end - start
perp = np.array([-direction[1], direction[0], 0])
perp = perp / np.linalg.norm(perp) * 0.22
label.move_to(mid + perp)

Graph Creation Pattern

self.node_to_circle = {}  # Dictionary mapping
for name, pos in positions.items():
    circle = Circle(radius=0.3, color=BLUE, fill_opacity=0.5, stroke_width=2)
    circle.move_to(pos)
    self.node_to_circle[name] = circle

Pedagogy (3b1b Style)

1. HOOK: Pose interesting question
2. INTUITION: Visual understanding (NO formulas yet)
3. STEP-BY-STEP: Concrete example with numbers
4. FORMALIZATION: NOW introduce formula/name

Rules (Detailed Reference)

Setup & Basics

• rules/manim-setup.md - Installation
• rules/scene-basics.md - Scene structure
• rules/color-scheme.md - Full color palette

Animation

• rules/animation-patterns.md - LaggedStartMap, state save/restore
• rules/text-transforms.md - TransformMatchingStrings
• rules/updaters.md - add_updater for dynamic motion
• rules/seamless-transitions.md - Smooth transitions

Layout & Visual

• rules/layout-spacing.md - Spacing, screen zones
• rules/mobject-grouping.md - VGroup organization
• rules/visual-quality.md - Quality checks
• rules/camera-work.md - MovingCameraScene

Content Types

• rules/equations.md - LaTeX, MathTex
• rules/graphs.md - Function plotting
• rules/3d-surfaces.md - ThreeDScene

Audio & Sync

• rules/audio-sync.md - Audio-visual sync
• rules/strict-sync.md - StrictSyncScene

Philosophy

• rules/pedagogy.md - Intuition before formalism

MUST / MUST NOT

MUST

• Use #1c1c1c background
• Use LaggedStartMap for cascading effects
• Group related elements with VGroup + dictionary
• End with self.wait(2) for padding
• Keep NODE_GAP >= 1.5
• Place edge labels perpendicular to edge

MUST NOT

• Use pure black (#000000) background
• Animate elements one-by-one with separate play() calls
• Place nodes too close (< 1.5 units apart)
• Show formulas before building intuition
• End play() without wait()