Open-source Physics Demos & Apps

⚠️ The URL redirects here due to technical issues. For the personal homepage of Yi-Ting Tu (Rick Tu), please visit

Ray Optics Simulation

A web app for creating and simulating 2D geometric optical scenes, with a gallery of (interactive) demos.

Home · Simulator · Gallery · GitHub

Balls Simulation

A simple web app simulating the collision of balls, linkage by springs, and their motion under gravity.

Simulator · GitHub

About PhyDemo

This website was originally part of Yi-Ting Tu (Rick Tu)'s personal website. However, as Ray Optics Simulation became a more and more non-personal project, and due to future consideration of new projects with some contributors, the original was split into and in December 2022, where the former is Yi-Ting Tu's new personal website.

This website, still (mainly) managed by Yi-Ting Tu, is intended for physics educational projects, including physics "demos" (instructions, videos, interactive images, etc., to show the physics directly), and physics "apps" (computer programs for users to build physical systems virtually, and to simulate them). However, due to the very limited spare time of the author(s), it is possible that no new projects will appear here for years.