The history of Alt+number sequences, and why Alt+9731 sometimes gives you a heart and sometimes a snowman

Once upon a time, the IBM PC was released.

In the IBM PC BIOS, you could enter characters that weren’t present on the keyboard by holding the Alt key and typing the decimal value on the numeric keypad. For example, you could enter ñ by holding Alt and typing Numpad1 Numpad6 Numpad4, then releasing the Alt key.
↫ Raymond Chen

Another Raymond Chen story, and this one involves hearts, snowmen, different editing controls, codepages, and more. In other words, just another Tuesday for Chen.