Character Sheet: Cody the CoderDojo Turtle

The canonical identity document for Cody, the pedagogical mascot for the Learning Computational Thinking with Scratch textbook. Every pose prompt and every piece of AI-generated content involving this character must re-anchor to the description below — it is the source of truth for visual and voice consistency.

Cody is gender-neutral. Always refer to Cody by name or with they/them. Never use he or she.

Identity

• Name: Cody
• Species: Turtle
• Subject: Computational thinking with Scratch (turtle graphics, loops, variables, custom blocks)
• Catchphrase: "One step at a time!"

The catchphrase carries the two ideas the course is built on at once: a turtle moves a number of steps, and a hard problem is solved by breaking it into steps.

Visual Description

• Body color: leaf green — hex #8BC34A, outlined in #55892C
• Accent color: CoderDojo purple shell — hex #642580, outlined in #43164F
• Shell plates (scutes): light purple #8E44AD, each rimmed in CoderDojo teal #41BAC1
• Belly plate (plastron): cream #FBEFC8 with #DCC48A seam lines
• Clothing / accessories: none — Cody carries a teal marker pen (#41BAC1, dark nib #26323F) in whichever hand is free. The pen stands for Scratch's Pen extension, which the whole course is built around. It is Cody's only prop and it appears in all seven poses.
• Expression: large round white eyes with a dark #26323F pupil and a single white sparkle highlight; soft pink blush cheeks (#F48FB1, 55% opacity); a gentle closed smile at rest
• Size proportion: chunky and small — head roughly the same width as the shell, short arms and legs. Designed to stay readable at 90 px.
• Art style: flat vector cartoon. Thick rounded outlines, no gradients, no textures, no drop shadows. Fully transparent background.

Age-Appropriateness Rules

The audience is elementary students in roughly grades 3–5. These rules are binding on every future pose or redraw:

• Rounded shapes only — no fangs, claws, spikes, horns, or weapons
• Oversized eyes and blush cheeks; a soft, open, friendly face at all times
• The "warning" pose is concerned, never angry: raised inner eyebrows and a small surprised mouth, never a scowl or furrowed brow
• No text, numbers, or lettering inside the artwork
• High contrast and simple silhouettes so the character survives being scaled to a 90 px admonition icon
• Nothing scary, sad, or scolding — Cody never expresses disappointment in the student

Personality

• Patient — never rushes the student, never implies a step should be fast
• Curious — wonders out loud, asks what will happen before it happens
• Encouraging — treats being stuck as a normal part of programming
• Playful — light and a little silly, but never sarcastic

Voice

• Short sentences and grade 3–5 vocabulary; one idea per sentence
• Never says a task is "easy", "simple", or "obvious" — a student who finds it hard should not be made to feel they are the problem
• Prefers try over know: "let's try it and see" rather than "you should know"
• Speaks about the program, never about the student's ability
• Signature phrases: "One step at a time!", "What do you think will happen?", "Let's try it and see!"

Pose Set

Pose	Filename	Use
Neutral	neutral.png	General-purpose / sidebars / forward links
Welcome	welcome.png	Chapter and lab openings
Thinking	thinking.png	Key concepts, predict-before-you-run questions
Tip	tip.png	Hints and helpful guidance
Warning	warning.png	Common mistakes / pitfalls
Encouraging	encouraging.png	Difficult content / "stuck?" hints
Celebration	celebration.png	End of chapter or lab, achievements

All seven are drawn at the same scale, then trimmed to their own content with a uniform 4 px transparent buffer, so each file is a tight RGBA PNG with a fully transparent background. Heights land within 363–371 px, which keeps Cody the same apparent size across poses when the images are letterboxed into the fixed 90 × 90 box that mascot.css gives .mascot-admonition-img (object-fit: contain). Widths vary with the pose:

File	Size (px)
neutral.png	236 × 363
welcome.png	300 × 364
thinking.png	267 × 368
tip.png	270 × 365
warning.png	307 × 365
encouraging.png	265 × 365
celebration.png	336 × 371

See image-prompts.md for the full text of each pose prompt. The base description embedded in every pose prompt must match this character sheet exactly.

How the Artwork Is Produced

The current pose set was generated as one coordinated text-to-image batch from the self-contained prompts in image-prompts.md, using the neutral pose as the visual identity reference for the other six poses. The batch renders onto a shared 400 × 392 transparent RGBA canvas; each file is then trimmed to the bounding box of its visible pixels (4 px buffer) and re-saved with PNG optimisation, giving the per-pose sizes listed above:

python3 ~/.claude/skills/book-installer/scripts/trim-padding-from-image.py \
  docs/img/mascot/neutral.png docs/img/mascot/welcome.png \
  docs/img/mascot/thinking.png docs/img/mascot/tip.png \
  docs/img/mascot/warning.png docs/img/mascot/encouraging.png \
  docs/img/mascot/celebration.png

Re-run the trim after regenerating any pose — untrimmed canvases make Cody render noticeably smaller inside the mascot admonition box.

The earlier deterministic vector set can still be regenerated from code:

python3 scripts/generate-mascot.py /tmp/cody-svg

That writes seven SVG files. They can be rasterised to transparent PNG with headless Chrome:

"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome" --headless \
  --disable-gpu --hide-scrollbars --force-device-scale-factor=2 \
  --default-background-color=00000000 --window-size=512,512 \
  --screenshot=/tmp/cody-svg/neutral.png /tmp/cody-svg/neutral.svg

To regenerate the current illustrated set, use all seven prompts in image-prompts.md in one session, keep the neutral result as the visual reference for the remaining poses, and then normalize every image to the canonical shared canvas.

Why This Mascot

Cody already existed in this book before the mascot was drawn: the very first lab, Draw A Square, introduces "Cody our CoderDojo turtle" as the sprite the student commands. Making that same turtle the book's pedagogical agent means the character the student talks about and the character that talks to the student are one and the same. The species is also the course's central metaphor — this book teaches turtle graphics in Scratch specifically to prepare students for Python's turtle module — and the purple shell with teal-rimmed plates carries the CoderDojo brand colors from mkdocs.yml.