This is a simple clock inside the terminal using ANSI Escape Sequences.
To build the program simply invoke
$ make
inside a terminal.
If you are on Windows and don't have enabled UTF-8 Encoding run
$ chcp.com 65001
inside your terminal to enable it inside the current instance. Also you have to use a TT (TrueType Font) for correct rendering. On Linux you shouldn't have any problems since most terminals use UTF-8 Encoding by default.
Tested Windows with Git Bash.