Jaap Scherphuis
@jaapsch.net
Mathematician, likes mechanical calculators, twisty puzzles, the Psion II, and tiling patterns. See https://www.jaapsch.net
“Are machines smarter than me?”
This 1949 ad for the Comptometer mechanical calculator discusses the question we are still struggling with now, and comes to the conclusion that grey matter beats any new-fangled machine.
This 1949 ad for the Comptometer mechanical calculator discusses the question we are still struggling with now, and comes to the conclusion that grey matter beats any new-fangled machine.
November 25, 2025 at 2:16 PM
“Are machines smarter than me?”
This 1949 ad for the Comptometer mechanical calculator discusses the question we are still struggling with now, and comes to the conclusion that grey matter beats any new-fangled machine.
This 1949 ad for the Comptometer mechanical calculator discusses the question we are still struggling with now, and comes to the conclusion that grey matter beats any new-fangled machine.
Some close-up pictures. It will be a while before this makes it to my website
November 15, 2025 at 2:41 PM
Some close-up pictures. It will be a while before this makes it to my website
My latest buy. I hope I can get this very heavy bit of machinery to work again.
November 15, 2025 at 2:41 PM
My latest buy. I hope I can get this very heavy bit of machinery to work again.
The ZX81/80 Print ‘N’ Plotter was a semi-transparent sheet that allowed you to trace pictures with pencil and pixelize them so that they can be approximately displayed on the Sinclair ZX81’s screen of 22x32 characters or 44x64 pixels. The sheet can be washed clean.
November 12, 2025 at 5:29 PM
The ZX81/80 Print ‘N’ Plotter was a semi-transparent sheet that allowed you to trace pictures with pencil and pixelize them so that they can be approximately displayed on the Sinclair ZX81’s screen of 22x32 characters or 44x64 pixels. The sheet can be washed clean.
Here you go. It was a properly produced thing, but I don’t know by whom. Here it is on a piece of A4 paper. It was just transparent enough to pencil trace over pictures, and the pencil could be washed off. As you can see, I was into maps.
November 12, 2025 at 5:15 PM
Here you go. It was a properly produced thing, but I don’t know by whom. Here it is on a piece of A4 paper. It was just transparent enough to pencil trace over pictures, and the pencil could be washed off. As you can see, I was into maps.
Thanks for the scan. Burt Harrison & Co provided learning materials for schools and home schooling, but I don't know how this reissue came to be.
archive.org/details/find...
archive.org/details/find...
October 23, 2025 at 6:29 PM
Thanks for the scan. Burt Harrison & Co provided learning materials for schools and home schooling, but I don't know how this reissue came to be.
archive.org/details/find...
archive.org/details/find...
Recently I bought this toy calculator from 1971. It is quite clever how its 2-digit register is shown not just as digits but also with columns of coloured dots.
October 22, 2025 at 8:55 PM
Recently I bought this toy calculator from 1971. It is quite clever how its 2-digit register is shown not just as digits but also with columns of coloured dots.
On an auction site someone is claiming to have a Comptometer for sale, but the picture is some kind of AI-generated rubbish. I don't see the point, but it makes for a fun game: How many errors can you spot?
October 12, 2025 at 10:53 PM
On an auction site someone is claiming to have a Comptometer for sale, but the picture is some kind of AI-generated rubbish. I don't see the point, but it makes for a fun game: How many errors can you spot?
@chrisstaecker.bsky.social It even came in the *original* box.
September 28, 2025 at 4:04 PM
@chrisstaecker.bsky.social It even came in the *original* box.
The instruction manual for the Facit NTK mechanical calculator included many pictures of the Facit Wizard.
September 28, 2025 at 4:04 PM
The instruction manual for the Facit NTK mechanical calculator included many pictures of the Facit Wizard.
This little guy is the Facit Wizard. It is the advertising mascot for the Facit mechanical calculators. His first appearance was in the 1950s.
1/3
1/3
September 28, 2025 at 4:04 PM
This little guy is the Facit Wizard. It is the advertising mascot for the Facit mechanical calculators. His first appearance was in the 1950s.
1/3
1/3
Maybe I'll be lucky and be the only bidder...
But seriously, that thing is valued at 500 times my whole collection, but does not function as well as a 5 dollar plastic one
But seriously, that thing is valued at 500 times my whole collection, but does not function as well as a 5 dollar plastic one
September 25, 2025 at 7:52 PM
Maybe I'll be lucky and be the only bidder...
But seriously, that thing is valued at 500 times my whole collection, but does not function as well as a 5 dollar plastic one
But seriously, that thing is valued at 500 times my whole collection, but does not function as well as a 5 dollar plastic one
Today I opened a box from my storage unit and pulled out six Contex B adding machines. These were in production from 1951 till about 1970.
September 21, 2025 at 8:58 PM
Today I opened a box from my storage unit and pulled out six Contex B adding machines. These were in production from 1951 till about 1970.
I’m not sure that’s going to do much
September 9, 2025 at 4:31 PM
I’m not sure that’s going to do much
I went to a large car boot sale today and found several calculators. Here are some pictures. I only bought the Odhner in the last picture, since I already had the others in my collection.
September 7, 2025 at 3:17 PM
I went to a large car boot sale today and found several calculators. Here are some pictures. I only bought the Odhner in the last picture, since I already had the others in my collection.
Here are two older Nationals I came across in an antiques store, both still installed on shop counters, though I don’t know how much they are still in use
August 16, 2025 at 5:29 AM
Here are two older Nationals I came across in an antiques store, both still installed on shop counters, though I don’t know how much they are still in use
It's been a while since my last calculator collection update, and this time it's not even a calculator.
August 10, 2025 at 8:09 AM
It's been a while since my last calculator collection update, and this time it's not even a calculator.
Deathwatch (2002) is a creepy horror movie set in WW1 that is far better than the reviews suggest.
July 5, 2025 at 8:06 PM
Deathwatch (2002) is a creepy horror movie set in WW1 that is far better than the reviews suggest.
My favourite convex monotile tiling with a high neighbour count is this one made of pentagons. The red pentagon has 8 neighbours. I don't think any other convex tile can beat this, apart from variations of the rectangle (or parallelogram) tiling above.
(2/2)
(2/2)
June 24, 2025 at 8:43 AM
My favourite convex monotile tiling with a high neighbour count is this one made of pentagons. The red pentagon has 8 neighbours. I don't think any other convex tile can beat this, apart from variations of the rectangle (or parallelogram) tiling above.
(2/2)
(2/2)
When a regular hexagon tiles the plane, each tile has 6 neighbours. In other tilings by a convex monotile, you can have more neighbours on some tiles by having others with less. The red tiles here have 8 neighbours. There is no upper bound, as you can simply use narrower strips to get more... (1/2)
June 24, 2025 at 8:43 AM
When a regular hexagon tiles the plane, each tile has 6 neighbours. In other tilings by a convex monotile, you can have more neighbours on some tiles by having others with less. The red tiles here have 8 neighbours. There is no upper bound, as you can simply use narrower strips to get more... (1/2)
Here are some pictures I just took of a small barred grass snake in the fish pond in the back garden.
June 11, 2025 at 3:03 PM
Here are some pictures I just took of a small barred grass snake in the fish pond in the back garden.
I've been working on another old mechanical calculator and had some trouble reading the serial number on the back. I wonder if it was the last one done before the weekend, or the first one the Monday morning after.
May 26, 2025 at 9:13 PM
I've been working on another old mechanical calculator and had some trouble reading the serial number on the back. I wonder if it was the last one done before the weekend, or the first one the Monday morning after.
I've been fixing up this lovely old mechanical calculator, a wooden Comptometer made in about 1902. Tomorrow I'll put it on my website and post a video.
May 8, 2025 at 8:30 AM
I've been fixing up this lovely old mechanical calculator, a wooden Comptometer made in about 1902. Tomorrow I'll put it on my website and post a video.
