About Sangathika

Who writes it

Sangathika is written by Niranga Dharmaratna. He is a lecturer in computing, based in Colombo, Sri Lanka. He teaches information security, software development and related subjects to university students. He designs and checks every lesson on this site.

The name is a Sinhala word, සංගතික. Its root means coherent: things that have gone together and fit. Read where the name comes from.

How a lesson is built

Each lesson teaches one idea, stated in one short sentence under its heading. You act first: you drag, set or step an object on the page. Then you predict what will happen, and only then do you read why. Each lesson ends with questions and challenges, and each challenge declares its level before you open it.

Lessons grow in leaves, and each leaf is a subject such as linear algebra. A few objects return across all the leaves, so what you learn in one leaf is waiting for you in the next. Read the method in full on the tree page.

Reuse in your course

You may link to any lesson, or to one demo on a lesson. You may also copy, adapt and share the text and illustrations under the Creative Commons Attribution-ShareAlike 4.0 licence. If you share an adapted version, it must carry the same licence. Please credit the work like this:

සංගතික · Sangathika by Niranga Dharmaratna, CC BY-SA 4.0, https://www.sangathika.com/

The code (JavaScript and CSS) is under the MIT licence. The name සංගතික, its spellings in other scripts, and the tree mark are not covered by either licence. An adapted version must use its own name.

Propose a lesson or report an error

To report an error, open an issue on GitHub. Name the lesson and say what is wrong. Each error that is confirmed is fixed and noted in the change log.

To propose a lesson, open an issue with five things: the idea in one sentence, what the learner does first, the mistake the lesson clears, the question it hands to the next lesson, and the lessons it builds on. The contributing guide explains the rest.

Privacy

This site has no accounts, no analytics scripts and no cookies. Your quiz progress and your choice of light or dark theme stay in your own browser. GitHub serves the pages and keeps its own traffic counts under its terms.

Credits

Fonts: Open Sans, STIX Two Text, IBM Plex Mono and Noto Sans Sinhala, each under the SIL Open Font Licence 1.1. Colours: the Solaris CDE Crimson palette. Every illustration is drawn for this site.

The lessons are made with the help of AI tools, under the author's direction. The author selects, edits and checks every page, and is responsible for it. Full notices are in the notices file.