is a simple emulation of the legendary HP 15 C Calculator on the Desktop. With UPN-Logic calculations are faster than the conventional way with the equals sign ( see Wikipedia).
It is possible to operate the calculator with the mouse and the numerical keypad. Functions are accessable by keyboards. It can be moved free on the desktop. With turning the mouse wheel the size of the calculator can be changed. The complex operations and the matrix operations are not yet implemented. Also it is not possible to program the calculator.