tn5250 is a 5250 terminal emulator, used for connecting to IBM's AS/400 (now known as eServer iSeries) midrange computers. tn5250 implements TN5250E, which means it is capable of device name selection, and printer sessions. The emulator supports color, 132 column mode, and most other features found in 5250 terminals and Client Access' 5250 emulator. While tn5250 is text-based application, a script is included to run it in an xterm properly. If you don't know what an AS/400 is, this program will probably not be of much use to you.
trojuhelnik is a general solver for triangles. It computes all possible solutions for a triangle that is specified by an arbitrary triple of the following elements: sides, angles, altitudes, medians, angle bisectors, area, radius of circumscribed and inscribed circle, sum a+b, perimeter and difference of the angles. All other elements, triangle visualization, and graphs of elements dependencies are also available.
Trowser is a browser for large line-oriented text files (such as debug traces). It's meant as an alternative to "less". Compared to less, trowser adds color highlighting, a persistent search history, graphical bookmarking, separate search result windows, and flexible skipping of input from pipes to STDIN. Trowser has a graphical interface, but is designed to allow browsing via the keyboard at least to the same extent as less. Key bindings and the cursor positioning concept are derived from vim.