Mate Soos <soos.mate@gmail.com>

Acknowledgements:
The author would like to thank in no particular order Horst Samulowitz,
Marius T. Lindauer, Martin Maurer, Martin Albrecht, Vegard Nossum,
Valentin Mayer-Eichberger, George Katsirelos, Karsten Nohl,
Luca Melette, Marijn Heule, Vijay Ganesh, Trevor Hansen and Robert
Aston for their help.