Jaap's Scratch Pad

I am Jaap Scherphuis, and this is my website.
I maintain several sub-sites here about things that interest me.

Jaap's Puzzle Page
Jaap's Puzzle Page
Articles about and solutions to many twisty puzzles
Jaap's Psion Page
Jaap's Psion Page
Everything about the Psion Organiser series II.
Jaap's Mechanical Calculators Page
Jaap's Mechanical Calculators
My collection of mechanical calculators, e.g. Comptometer, Curta.
My research into periodic tilings that use a single polygon tile.
Gathering for Gardner Exchange Gift
Gathering for Gardner
Exchange gifts, papers, and talks for the G4G conference.
DIY-Gamer Kit by Technology Will Save Us
DIY-Gamer Kit
A simple programmable game computer by TWSU based upon an Arduino.
DigiRule by Bradley Slattery
DigiRule is a programmable binary ruler, from a Kickstarter project by Bradley Slattery.
Antique 26-sided Stone Die
26-sided Die
This 26-sided die was made in about 1890 in Zöblitz, Germany.

Here are a few other bits that don't have their own pages.


Downloadable version of my puzzle page, excluding the patent pdfs and large gallery images: puzzles.zip (36.4 MB)
The puzzle patents: patents.zip (86.0 MB)
The gallery: gallery.zip (676 MB)

Here are some javascript puzzle scramblers:
   Rubik's Cube Scrambler for any size cube.
   Megaminx Scrambler.
   Square-1 Scrambler
   Rubik's Clock Scrambler
   Rubik's Clock Scrambler, graphical version
   Rubik's Ufo Scrambler.
   Download all scamblers.

Sudoku generator. Fast generator/solver for various sudoku variants. A Java applet.


My YouTube channel. Most of the videos are related to the mechanical calculators, but a few of the early ones are of magic tricks that I invented.


Ever-increasing Beat is a quick demo of an auditory illusion used in the score for the movie Dunkirk.

Here (600K wav file) is a voicemail message someone left on my mobile phone some time in 2002. It is in a kind of German, and rather funny.

I have an old nokia phone (6021), and have written programs for it. To install a program on a Nokia you need the PC Suite software.
Twister.jar, Twister.jad, Source Code. Puzzle game, like a 2d version of the Rubik's Cube.

Written by Jaap Scherphuis, website a t jaapsch d o t net.