Today I tried to design a laser-cut set of Soma cube pieces. The pieces (shown above) are (conceptually, and sometimes actually) made of 3D blocks glued together.

I've seen a particular style of joinery for acryllic, called finger joints. Those looked easy to cut and easy to put together (if hard to design).

I wrote a python script that takes a description of a piece, like this:

Piece E
xx x-
x- --
-- --

And draws all the flat faces I need to cut.

I was already running far behind, time-wise. I ran out of time before I could get the joinery working. Honestly, I don't think I'm very close, either.

How to do a three-piece corner join was especially confusing me.

I wrote a player for #ircpuzzles, a yearly puzzle hunt hosted on IRC. Many people who might like to try the puzzles don't know how to use IRC. So, now you can replay past years online.

I didn't have time to finish this one. It only has one year, and is missing a little polish. I'd call it about 80% done. It worked as a warmup for hack-a-day, my yearly project to complete one project a day in November.

Demo is here. Source is on github.

Oops. Everyone, in the entire world, forgot what time it was. Maybe we all forgot the change the batteries for 500 years.

Today's question is:

How do you figure out the exact time, down to the millisecond, without referencing a running clock?

This question courtesy of ems

Feel free to send answers to me by email. I'll add interesting answers to the post.

Ingredients needed:

• Foam paintbrush (Home depot, $0.80)
• Black tea (I used Meijer brand, 100 bags for $2.50)
• White flour (for multiple-page scrolls)
• At least one cookie-baking sheet

Optional extras:

• Gold washi tape, or other decorative tape ($8)
• Ribbon ($15 for 36 colors) to tie the scrolls shut
• Wax ($10), and a seal ($8), to add seals to the scroll
• Lathe, hand saw, dowel rods ($5 for 1" x 4ft / 25mm x 1.3m), paintbrush ($3 for 20), stain ($8) and varnish ($17) to make your own holding rods. If you don't have a lathe, see other suggestions.
• String ($3-7 for 500ft / 200m) or steel rope ($43 for crimping tool, $13 for cutting pliers, $22 for 1/16 inch x 300ft / 1.5mm x 100m rope) to hang the scroll
• Paintbrush ($3 for 20) and stencil ($7-$15) for decorating the back

First, I aged the individual sheets.

1. Soak 8 black tea bags in 2 pints boiling water. Let it sit at least 10 minutes.
2. Print the paper you want to stain.
3. Dip the foam paintbrush into the tea. Let large, splashy drops fall onto each piece of paper. Cover 30-50% of the paper. Leave it out until dried (several hours). This is the slowest step, but yields a pleasant, uneven look. For an even better look, place a teabag on the paper repeatedly, then let it dry, then repeat again in the empty spaces and let it dry again.

   

   

4. Take each dried sheet, and place it on a cookie tray. Again dipping the brush in tea, paint over it several times, making sure to cover the whole sheet. Use varied directions for brushstrokes. You may not be able to see any visible stain. You don't need to soak it fully, but you can.

   

5. Take the cookie sheets, and place them in the oven. I baked them for 250°F for 6 minutes. This was just enough so the sheets were dry to the touch. This not only dries the sheets faster, but activates the tea and makes it take on a much darker tone.

   

6. If desired, you can paint a second pass on the back--the tea will only stain one side at a time deeply. I recommend doing the back second, because each bake makes it a little darker.

   

7. Press sheets flat under a large, heavy book.

In theory I think you can iron the sheets flat. If I did this project again, I would try it. It's hard to line up and glue wavy sheets.

I tried painting on the back, using a paint I made myself. I wanted something subtle, like the faint patterning on decorative paper. I tried tempura paint, using coffee in place of water, and flour-based tea paints. I got something that looked how I wanted.

I liked the effect, but I had a hard time reproducing the paint the next day. If you want to experiment, my recipe used something like 1 bag of tea, one cup of water, and about 2 Tbsp flour.

Next, I glued together the sheets to make a continuous scroll. For reasons you'll see later, I needed an extra strong glue. So as my first step, I made wheatpaste glue, which is very strong.

1. Combine in a paper bowl:
   • 25g flour
   • 75g water
2. Stir thoroughly with a fork.
3. Microwave for 1 minute, then stir again. Repeat.
4. Once it's thick enough you have a harder time moving a fork through (2-3 minutes with my microwave), let it cool.

   

I glued together the sheets with wheatpaste. For some projects, it's easier and better to apply warm. But my paper was already fragile from the aging process, so I found it worked better all the way cooled.

I took a fingertip of glue, spread it evenly on the bottom of the page. Repeating, I covered the whole bottom. Then, I placed the next sheet over it, and laid them down so they matched. Since the aging process warps the paper, you may not get a perfect fit.

Then, use the pad your your thumb to press the sheets together firmly. Make sure to use rolling motions, don't drag your finger along. That can tear the paper.

My research suggested Zip Dry paper glue might also work.

As a fun fact, real scrolls were made by gluing together sheets, and they actually used wheatpaste glue! Scrolls were often glued left-to-right (volumen) instead of top-to-bottom (rotulus), but I thought the fantasy stereotype was more fun.

After the glue hardened, I cleaned off both sides and trimmed the edges to match exactly. Then I applied a gold tape on the edges. I had decorative borders printed already, so it was relatively easy to get tape pieces to match. I found the key was to go slow, and use many pieces of tape. After laying one down, I pressed it smooth with the back of a fingernail, flipped it, and did the same of the back. The washi tape I'm using is relative easy to remove again, but also shows defects pretty clearly.

I turned dowel rods to hold the scroll on my lathe. The middle segment is the width of a piece of paper. Then I added as much decoration as I could on each end, but my lathe is very small, so not much fit.

Then I stained and finished the dowel rods.

If like most people you don't have a lathe, you could glue something decorative on the ends of dowel rod pieces, cut bamboo segments, or decorate a paper towel roll.

It's also totally fine to just roll up the scroll and tie it closed with string or ribbon. No holders are really needed.

I made another batch of wheatpaste (much better this time).

I glued the scroll onto the dowel on the two ends.

The glue was very strong, but the ends only look okay. I trimmed the last couple inches of washi tape so the glue would stick.

If I did the project again, I'd try to keep the sheets flattened (wrinkly sheets after aging causes all kinds of problems). I'd also leave a little blank space on the top and bottom for attaching them to the rods.

I picked up some stranded steel rope, which I turned into a line with two loops at the end.

I looped them over the holes in the dowel. Voila! Now you can hang the scroll on the wall.

It's possible to make the wire hangers secure, but removable. For the first couple I made they're just secure--those suckers aren't coming off.

I dripped wax on the scroll and pressed down a seal I got on Amazon. It matches the theme of my D&D game very well, I was happy with how it looks.

The final scroll looks amazing.

One one hanger, it takes up the wall.

Between 6 pages and a dowel rod, that's why the glue between pages needed to be so strong!

By using two sets of hanging wires, you can show part of the scroll without taking up the whole wall. Here I'm showing the top of the scroll.

You can roll one dowel as you unroll the other, to show any part of the scroll. That's why long scrolls have two rods. It's also where the term "scrolling" up and down on a computer comes from.

I let each player pick the color of the wax for the seal and decorative ribbons. They didn't know exactly what they were giving me colors for.

I'm sure my players will love them!

By the way, if you're curious about the contents, this is a prophecy the players found in parts around the world. Underneath each of the 50 lines, are their player notes about where they found each piece. It's a souvenir for a campaign which ran for about 2 years, and is finally wrapping up.

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.