- A MATLAB script that plays music.

Download: play.m and Prelude.m
(The tone color is not well tuned.
No comment is provided.
But the code is not difficult to understand.) - A MATLAB script that draws a heart.

Download: heart.m

A similar figure drawn by MetaPost: heart.mp - A template for presentations in LaTeX.

Download: Standard (4:3) Wide Screen (16:9) (source) - A LaTeX template for wechat articles.

Download (source) - Pokers with many flags drawn by
MetaPost and LaTeX.
- Linux analogue
of the
`open`

command - What's the maximum branch factor in
Xiangqi
(Chinese chess)?

Find an answer here.

FEN: 5C3/2r1P1rPc/2P1k1Pcb/1C7/2N1N1Pnp/3R5/R8/4B1p1B/4A3p/p1n1K2p1 w - - 0 56

The red player has 111 different choices. - A calculator without number pad
and elementary arithmetic.

It can be shown that in exact arithmetic all rational numbers can be produced by this calculator. - The Lights Out game.