Chris Spackman’s NeoCities Page

Welcome to Chris Spackman’s NeoCities page

I loved GeoCities back in Japan in the 1990s, so was thrilled to discover NeoCities. I’m using this site mostly for educational tools and JavaScript experiments that I make for my schools and classes, and for other teachers and students.

Everything here is free to use. Please don’t hesitate to email me at chris@chrisspackman.com with bug reports, suggestions for improvements, or requests for other teacher-tool pages.

News

2026-08-15: Added the Enhanced Reading Page Builder — mark up a reading with speaker tags, vocabulary glosses (in up to two languages), teacher notes, and collapsible sections (chunking), and it builds a single self-contained HTML page your students can read with exactly the supports they need switched on. Readings print with only the supports shown, and can also be downloaded as editable Word handouts — pictures included — for Google Drive and Classroom. It is in Reading & Text Tools.

2026-08-15: Added a new Accessibility section, starting with Contrast Tools currently with three tools in one page. The checker takes the colors you give it and tests every pairing against WCAG contrast standards, showing which ones need fixing. The finder takes one or two colors you want to use (for background, body text, headings, or accent) and suggests accessible colors for the remaining roles. Finally, the slide-template creates a one-slide PowerPoint pptx file using your colors, with its boxes stacked in the order a screen reader reads them. Options include a weekly calendar where each day’s heading is read right before that day’s text. (The pptx file should import cleanly into Google Slides.)

2026-08-14: Updated Solar Expats: Beyond The Cradle to version 1.15.0 with balance changes and improvements from play testing.

K–12 Supports

Browser-based tools for teachers and students — especially for reading, phonics, and English Learner support. They run entirely in your browser, with nothing to install.

Reading & Phonics

Word List Builder Generate phonics word lists filtered by the sounds and patterns you have taught. Blending Practice Break decodable words into sound boxes for blending and segmenting practice. Sound Checker Check which sounds and graphemes appear in a word list or reading passage. Sentence Creator Build simple decodable sentences from the sounds and words a student has learned.

Word Games & Puzzles

Bingo Generator Print custom bingo sheets from your own list of words or terms. Word Search + Crossword Make printable word searches and crosswords from a vocabulary list. Word Scramble Create letter-scramble and sentence-scramble worksheets with answer keys.

Reading & Text Tools

Readability Checker Score the reading level of pasted text or a PDF, with suggested EL supports. Reading Modification Analyzer See how much a differentiated text actually differs from the original. Side-by-Side Reading Generator Lay an original and a modified reading side by side, ready to print. Speed Reader Read pasted text, .txt, or EPUB files at an adjustable words-per-minute pace. Enhanced Reading Page Builder Build interactive readings with speaker highlighting, two-language glosses, chunking, and printable or Word handouts.

Classroom Tools

Classroom Display Board Put directions, a clock, countdown timers, and a random name picker on the projector.

Study & Review

Flashcards Spaced-repetition (Leitner) flashcard review that runs in your browser.

Accessibility

Tools for making classroom materials — and web pages — easier for everyone to read and use.

Contrast Tools Check colors against WCAG contrast standards, find new colors that fit, and download slide templates with an accessible reading order.

Math & Probability

Coin-Flip Probability "Flip" any number of coins and watch the law of large numbers at work.

Cryptography & Code-Breaking

Interactive demos that explain how ciphers work — and how they get broken — from pen-and-paper classics to the math behind modern key exchange.

Traditional Cryptography Seven classic pen-and-paper ciphers, from trivially breakable to unbreakable. Early Modern Cryptanalysis Codebooks, the Zimmermann Telegram, the Black Chamber, and Friedman’s methods. Cryptanalysis: Breaking Ciphers Hands-on tools for breaking substitution, Vigenère, and transposition ciphers. CODEX Codebook Suite Build, use, and break codebook ciphers with an encoder, a maker, and a decryptor. Simplified Diffie-Hellman How two people create a shared secret over an insecure channel. Public/Private Key Generation The math behind creating a public and private key pair.

Command Line & Computing

Point-and-click helpers for some powerful but fiddly tools.

commandCraft GUIs that build commands for ten CLI tools (curl, ffmpeg, find, GPG, rsync, and more). regexCreator Build, test, and learn regular expressions interactively. nftables Builder Construct nftables firewall rules with a guided interface.

Just for Fun

2076: Sengoku America A game of legitimacy, influence, and war across a fractured USA. (Currently version 0.9 beta 1) Solar Expats: Beyond The Cradle Settle the solar system: colonize planets, trade, and out-build six rival factions. (Version 1.15.0) neojongg A mahjongg solitaire game. Every board is guaranteed solvable, and the Daily game is the same for everyone. Fortune An online version of the classic BSD / Linux fortune program. Age Verification A proof-of-concept: can you prove your age using historical knowledge?

Reference

Glossary of Terms Plain-English definitions of the math, cryptography, and probability terms used across these tools.

My Other Sites

Disclaimer: these pages are educational demos provided as-is, with no warranty of any kind. The author is not responsible for any consequences arising from their use.

Send comments and bug reports to chris@chrisspackman.com.

Last updated: 2026-08-15

This page is Copyright © 2024 – 2026 Chris Spackman.
This web site developed entirely on GNU/Linux.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Creative Commons License