The program ptp is a command line application intended for planning a particular kind of one-person projects. A detailed description is available here. The following diagram was created from the data of a project which used this software; the diagram was generated with mtdgnuplot (which is also part of this package) and the publicly available gnuplot software.
This software is released under the terms of the GNU GPL, version 2, and can be found in the directory http://home.vrweb.de/martin.lottermoser/ptp/dist. The package is available as a gzipped tar archive of source files (ptp-version.tar.gz); I am no longer providing Debian packages. The distribution directory contains also digital signatures for the published files (*.sign).
You will need a C++ compiler in order to create the executables yourself.