He has made contributions working on both the square packing problem and the magic tile problem. In 1979 he discovered the optimal known packing of 11 equal squares in a larger square, and in 2003, along with Christian Boyer, developed the first known magic cube of order 5. In 2009 he pioneered work on water retention on mathematical surfaces. In 2010 he placed first in Al Zimmermann's programming contest which asked contestants to find the maximum water retention for magic squares order 4 - 28. This specific work found a more general application in statistical physics with the resulting 2012 Physical Review Letter " Retention Capacity of Random Surfaces" which he coauthored . In 2014 he and Francis Gaspalou were able to calculate all bimagic 8x8 squares 
Walter Trump works as a teacher for mathematics and physics at Gymnasium Stein (retired 2016).
- Konhauser, Joseph D. E.; Daniel J. Velleman; S. Wagon (1996). Which way did the bicycle go?: and other intriguing mathematical mysteries. Cambridge University Press. p. 105. ISBN 978-0-88385-325-2.
- Niederman, Derrick (2009). Number freak: from 1 to 200— the hidden language of numbers revealed. Penguin. p. 63. ISBN 978-0-399-53459-1.
- Al Zimmermann http://www.azspcs.net/Contest/MagicWater/FinalReport
- Knecht, Craig; Walter Trump; Daniel ben-Avraham; Robert M. Ziff (2012). "Retention capacity of random surfaces". Physical Review Letters. 108 (4): 045703. doi:10.1103/PhysRevLett.108.045703.
- W. Trump">W. Trump http://www.trump.de/magic-squares/
|This article about a German mathematician is a stub. You can help Wikipedia by expanding it.|
|This article about a German scientist is a stub. You can help Wikipedia by expanding it.|