I'm a member of B.C. Tongelbridge and Bridge Inn.
My bridge interests have caused the development of the Portable Bridge Notation, and
the programming of BbnOrganiser , a program for handling bridge bidding systems.

  1. I developed a nice algorithm to generate figures with hexagonal characteristics: H6X9H.
  2. I proved that taking a stroll on a sunny day can best be done clockwise: zon.pdf (in Dutch).
  3. Computation of angles for a (stained glass) lampshade.
  4. The computation of the spiral center of triangles and quadrilaterals: spiral_center.pdf or in HTML.
  5. Four-armed spiral tiling of scalene triangles: four_armed_spiral.pdf or in HTML.
  6. Logarithmic spiral tiling of hexagons: hexagon_spiral.pdf or in HTML.

T'ai Chi Ch'uan
I'm learning the Yang style of professor Cheng Man-Ching as taught by Jeannine Geris, see taichibrabant.

Software engineering
I'm very much interested in the design of software components of real-time embedded systems from a professional point of view. Refer to my documents.
Reviewing software and documents is one of my specialties: refer to my errata.

  1. I made a water wheel of Plexiglas containing 4 inner wheels. Click on the picture to see it running chaotically.

  2. This impossible triangle of Plexiglas cubes is known from Oscar Reutersvšrd. It causes even more confusion if you click on it and see it rotating.

A long time ago, I was very familiar with chess. In 1980 I have beaten Korchnoi in 22 moves.
I am interested in computer chess, and a member of CSVN. See also ICGA.
Some time ago, I played two games at as RanaCidu.

For hobby purpose I have made programs for Commodore-64, Amiga 500, Amiga 4000, Java platform.
I made several Android apps, see Projects.
Currently, the focus is on Java application Tissellator, that creates Escheresque images.

Dance Dance Revolution
The ideal game for every age: fitness, brains, and fun (for 2).

I just like playing with a yoyo, like this guy:

GPS routes
Willingen + map

Pokemon Go
RanaCidu Team Mystic (blue).
Best friends with MysteryMoron, WatLeukToch en BlauwTien.
Level 40 @ 25 September 2017.
Level 50 @ 19 August 2023.