Like other employees, professors retire when they turn 65. But there are exceptions. One of them is computer pioneer and puzzle creator Prof. Willem van der Poel (87).
I‘I’m there every Tuesday morning,’ Van der Poel said. ‘I just stop by.’ The emeritus professor shares a room in the EWI tower. Ten stories below, there are computers that he built over sixty years ago. The relay computer Testudo, dating from 1952, is in the basement – or at least parts of it are. It counted at a rate two times slower than a human, but it remained in use for twelve years. The Zebra (1956) is also part of the study collection, proudly displaying 498 tubes and 509 transistors.
Today he is writing an entry for the Nieuw Archief, the magazine of the Royal Mathematical Society. The magazine published a puzzle (Is there is a number, n, such that the numbers 2n, 3n, 4n, 5n, 6n, 7n, 8n and 9n start with 2,3,4,5,6,7,8,9?), to which, after a few weeks of working, he has found the answer: no. Van der Poel says that the main difference compared to his activities before retirement is the fact that the supervision of assignments, and the help of the students involved in that, no longer feature in his work. Instead, he now gives readings, for which he is invited about ten times a year by, among others, the KNAW and the HCC (Hobby Computer Club).
He is also an active member of an international puzzle club, whose three hundred members devise, make and try to solve mechanical puzzles. ‘If I get my hands on a puzzle, it may take me three months, but I have to find a solution.’ That is what happened with Rainer Popp’s
Padlock One – a padlock with no lock or opening. He has two thousand puzzles at home and he pulls a whole range of them out of his bag.
he’s also rekindled his interest in computers. He started at the Technical University in 1962 as Professor of the Theory and Construction of Computers (applied logic). In the 1980s, his attention shifted from hardware to software, because of the rapid developments and considerable investments involved in constructing the former. However, the new, affordably priced microcomputers that are now appearing on the market have reawakened his interest in technology. A plastic box the size of a packet of cigarettes contains an ARM computer costing €35. It runs on Linux. Van der Poel types something into the keyboard and the computer calculates pi. The screen starts to fill up with numbers. The little thing can even simulate the old Zebra.
Puzzles, software and computers – Van der Poel is insatiable when it comes to logical challenges. However, there has also been a second career in the background: music. He learned to play the piano when he was five years old and he never gave it up. Later he learned the flute and the bassoon. He played with the student orchestra Krashna Musica for seventeen years. But he is glad he chose the TH and not the conservatoire. ‘For music you have to really be at the top of your game,’ he says with irony. And his motto? ‘Keep searching’ – but not intended in any