My family and I have been playing Curse of the Dark, an "escape-room" style board game. We recently reached the halfway point, where they recommend taking a break--it's supposed to be two 90-minute play sessions (spoiler: we are on month 6).

Included with the box is an answer sheet, which include scratch-off hints. (You might also be familiar with them from lottery tickets.) You scratch off the grey stuff with a penny, and underneath is the hint. I idly wondered if you could do that yourself.

I found several people online repeating this recipe:

• 2 parts silver acrylic paint (I used 5 parts white, 1 part black)
• 1 part dish soap

They recommended 2-4 layers to make it opaque. I gave it a try.

So visually it looked pretty good. But scratchable, not so much. It was hard to get off, and the paper tore when I scratched harder.

Randomona did some experimentation, and had better luck with all types of paint. Turns out it works way better if you add a layer of plastic, such as tape, rather than applying to paint directly to paper or cardstock. This makes sense since the stickers are basically a thin layer of something on tape. And sure enough, when I looked at the 2-3 other tutorials I read, they all said to apply tape first. Whoops!

I would discover this only later, pictures are later in the post

I decided to give "the reveal" a try with small square post-it notes (50x50 mm, about 2x2 inch).

These were okay. But

• not many fit on a page
• post-its aren't very fun to take off
• sometimes I had to use two notes, or you could see through
• my local store doesn't sell the full-sticky post-its, so you can peek if you really wanted. (I'm not sure if they still make full-sticky, and I don't think they ever did in mini size)

By the way, you can print your own using my bad generator. If you want less than 15, just leave some boxes blank and don't cover them with a post-it.

Next up, I bought some! They sell premade scratch-off stickers. They are available in 50x50 mm, but I went half that size--I'd rather have more on a page.

Mine came in a roll of 1000 stickers for $10 (that's 1 cent per sticker). You can get circles or squares--I picked squares.

Here you can see my scratch-off chores card. It was a lot more fun. I wrote a better second generator you can use to print your own. Up to 88 can fit on a page, and it will shrink the grid if you have less.

Finally, I tried the homemade acrylic paint method a try, with tape this time.

I'd say the stickers scratch off best, followed by the recipe mentioned on tape. I tried more dish soap and no dish soap, and they were both worse. I suspect less dish soap would work better.

You can write on the stickers fine, or the acrylic, but the dish soap recipes scratch off if you try to use a pen on top.

What's the longest sequence of words you can make, beginning with any word and adding one letter at a time, if each step must also be a word?

If you can add them only at the end, a computer search outputs the dubious:

co
com
comp
compo
compos
compose
composer
composers

Adding letters only at the beginning I get the equally doubtful:

es
hes
shes
ashes
lashes
plashes
splashes

If you add can add letters on either end, I found this valid 10-letter sequence:

I
in
tin
ting
sting
siting
sitting
slitting
splitting
splittings

My personal favorite, allowing rearranging letters, yields this whopping 15-letter series:

I
it
tie
rite
irate
attire
cattier
interact
intricate
recitation
ratiocinate
ratiocinated
accreditation
contraindicate
contraindicated

The above answers found using a python, and the GNU aspell dictionary. Words containing ', -, or capital letters were removed.

I've been keeping track of my daily exercise using a checklist on the wall.

I wanted a nice small printable one. I looked around, and there were several for sale for $2. I made a free one, instead.

Here's the download link: 26 row. Or if you hate blank rows, here are some with less rows: 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

And of course, I customized one with my own workout routine.

I've changed the backend of my blog. You shouldn't notice any differences, except that comments are disabled for the time being.

All links to the site should continue to work.

If you notice any problems, even small ones, please send me an email.

Lately I’ve been messing about in Godot, a framework for making video games (similar to Unity).

I wanted to make a 3D game. In my game, you live in a geodesic dome, and can’t go outside, because mumble mumble mumble poisonous atmosphere?.

A geodesic dome, I learned, is related to the icosahedron, or d20 from RPGs.

A simple dome is the top half of the icosahedron. As they get more complex, you divide each triangle into more and more smaller triangles.

So to make a nice geodesic dome, we could find one (I failed), make one in Blender (too hard), or use some math to generate one in Godot. And to do that math, we need to know the list of 20 icosahedron faces. Which basically just needs the list of the 12 vertices!

Now, obviously you could look up the vertices, but I thought of a more fun way. Let’s put 12 points on a sphere, make them all repel each other (think magnetically, I guess), and see where on the sphere they slide to. Maybe they will all be spaced out evenly in the right places. Well, here’s what it looks like:

So… kinda? It was certainly entertaining.

By the way, the correct coordinates for the vertices of an icosahedron inside a unit sphere are:

• the top at (0, 1, 0)
• the bottom at (0, -1, 0)
• 10 equally spaced points around a circle. they alternate going up and down below the center line.
  (±1/√5, sin(angle), cos(angle)) [projected onto the sphere]

Sometimes Linux wants to open files. I mostly use the command line, so I wrote some helper programs to open things in terminals.

• open-text-file opens your default text editor in a terminal. I set it as my program to open all text files.
• open-directory opens a terminal with that working directory. I set it as my program to open all directories.

They’re both available in short-programs. Both default to xterm.

When you click an email address, it automatically opens in your email client. But I don’t have an email client, I use webmail. I wrote a custom handler for Linux.

First write a program to open mailto links. Mailto links look like “mailto:me@mail.com” or maybe even “mailto:me@mail.com?subject=mysubject&body=mybody“. Test it by hand on a few links. Mine (mailto-opener) composes a new message using my webmail.

Next, write a desktop file for the opener. Here’s one:

#/usr/local/share/applications/mailto-opener.desktop 
[Desktop Entry]
Type=Application
Name=mailto: link opener (github.com/za3k/short-programs)

# The executable of the application, possibly with arguments.
Exec=/home/zachary/.projects/short-programs/mailto-opener %u

Note the %u in the Exec= line. That’s required.

Now update your system mimetype database. On my Arch Linux install, I run

xdg-mime default mailto-opener.desktop x-scheme-handler/mailto

Finally, restart your browser. Really. Firefox and Chromium/Chrome both cache mimetype openers.

A related opener I added recently was for magnet links, such as are popularly used for bittorrent.

~ $ cat /usr/local/share/applications/transmission-remote.desktop 
[Desktop Entry]
Type=Application
Name=transmission-remote magnet link opener
Exec=transmission-remote <TRANSMISSION INSTANCE> -a

transmission-remote is the name of a command-line Linux program. It connects to an instance of Tranmission (a popular torrent client) running on another machine.

I’ve been designing a keyboard and case for the zorchpad.

There are four pieces in the first iteration.

A top bottom base, to enclose the keyboard electronics.

A keyboard plate. The keys fit into the holes here. You type on the top, electronics go in the bottom.

A top plate. You see the screens, and switches through the cutouts. Otherwise, it keeps the behind-the-scenes wiring out of sight.

And finally, the top piece.

Here are the pieces in correct position. In the top will be the screens and battery. The bottom is a keyboard you type on. The whole things is meant to fold on a hinge, much like a laptop.

The same pieces, spread out.

There were many, many problems with the first design and the first print. I’ll talk about them (and my fixes) in my next post.

The Zorchpad needs a custom keyboard. Its power budget is only 1mW, and there’s just nothing available in that range. So, I need to make a custom keyboard. I started reading up on how to make your own–especially the electronics.

I don’t know how to make a PCB:

Or how to attach headers to the inside of an existing keyboard, which looks like this–:

But I found a project called GOLEM with an excellent guide to making your own keyboard. Here is their wiring:

I can do that! They got me out of a major rut.

Their advice walks you through how to do a small keyboard in a cardboard plate. I did a few keys, gauged the effort, and decided to use my 3D printer. Cutting out 50-60 keys precisely by hand doesn’t sound easy. Worse, if you mess up, you have to start over. In plastic, I can’t mess up halfway, and the spacers to support the keyboard can be part of the print.

Above, I’m designing a “sampler” keyboard in CAD (OpenSCAD). I want to iron out problems in my process before I try a full-size keyboard. Below, Prusa-Slic3r is slicing the finished model for my 3D printer to print.

Here’s the finished sampler keyboard:

Currently I’m waiting on keycaps and switches ordered from China, and then I’ll put together my finished keyboard. But I have been making some progress in the meantime. Here’s the layout I’m going to try.

And I’ve started streaming some development of a case and keyboard on Twitch (Tue/Thu 12pm noon, EDT). Feel free to join! Anyone can watch, but you need an account to chat.