Shareware / Careware

JVS (Java Structure Viewer)

JVS is a java package for visualizing the structure of quasicrystals such as the one shown below.

Vim

Vim is a highly configurable text editor built to enable efficient text editor. It is an improved version of the vi editor distributed with most UNIX systems.

Vim is often called a "programmer's editor," and so useful for programming that many consider it an entire IDE. It's not just for programmers, though. Vim is perfect for all kinds of text editing, from composing email to editing configuration files.