Repulsive Dots

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.

Icosahedron getting more and more detailed. Geodesic domes are the top half of each sphere.

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]

Garden signs on wall tiles

I’m making labels for my garden sections by painting tiles.

This is a blank “subway” style marble tile. It’s 140×45 mm (2×6 inch). One is about $1. Avoid “glazed” or “glossy” tiles, which are too smooth for the paint to stick well.

First, we add a layer of tape. I used blue painter’s tape because it’s easy to see. I expect masking tape would work well too.

Attach the sign you want to your tape. I used double-stick tape. It’s better than single-stick around the edges, but that also works in a pinch.

Cut through the letters using an x-acto blade. I used a sans-serif font to make this step faster.

Remove the paper, as well as the tape. You can use the x-acto blade to peel up the tape. Make sure not to lift up the “holes” in letters like ‘B’ or ‘a’.

Paint the tile. I used pale/pastel blue acrylic spray paint. Make sure to either not spray the sides, or cover them in tape too.

Then I let it sit for 15-20 minutes.

Peel off the tape. I used gloves, and took out the holes using tweezers.

Peeling the tape while the paint is slightly wet is easier than completely dry. When it’s dry, the acrylic clings to the tape and “stretches” rather than cleanly breaking.

If you mess up along the way anywhere, acetone took the paint off great for me.

Then I let the paint completely dry. Optionally, you can seal it with a clear sealant if you want extra waterproofing.

I attach the tile to my raised beds using z-brackets sized to fit the tile thickness and a screwdriver. They look fine on the dirt too.

Looks nice! Maybe I’ll switch to a higher-contract color paint for white?

Making signs on wall tiles

I recently made an art project as a birthday gift for a young friend of mine.

I hadn’t seen the exact technique I invented to make stencils posted anywhere, so I figured I’d share it. I don’t think this is a good method, but maybe it will inspire someone to do something better.

I started with a blank tile. On top, I put down a layer of painter’s tape (basically masking tape, but a little less stretchy).

I printed and taped a piece of paper on top (made using this online tool with the font BreeSerif):

I used an x-acto knife to cut through both the top paper and paper, then removed the paper. Then I peeled the letters out of the painter’s tape.

I painted the letters with acrylic, let them dry, and removed the tape. In retrospect, it probably would have been easier to remove the tape wet, because acrylic paint is a little stretchy and I went over the lines.

The letters happily lifted right off the glazed tile, which hadn’t been sanded or anything. I added a heavy coat of modge-podge spray sealant, which kept everything in place after drying.

Finally, I used a masonry bit to drill screw holes in the tile, so it could be attached to a door.

She seemed to like it :). But now she wants to make one too. I’ll have to see if I can invent an easier way.

ircpuzzles! 2024

I’m one of the designers for the yearly April Fools Puzzle Contest on IRC.

Please feel free to join at The idea is that you solve puzzles in a chatroom, and get the password to the next chatroom, and so on. If you’re not familiar with IRC, don’t worry–a link is provided to connect in your browser, too.

It’s a lot of fun, and I hope you enjoy!

P.S. The contest should be up for a while, so don’t worry about being late to the party!

Bánh Chưng

A few friends and I first experienced this traditional Vietnamese Tết (Lunar New Year) food while visiting years ago. We loved it, and recently I looked up how to make it myself. It’s not a well known food in the US, so I thought it would still be fun to share.

I followed the recipe from “Enjoy a simple life“, but made a homemade cardboard mold as suggested by “Takes Two Eggs“.

Like a bread, this recipe takes a fair bit of time. I would start in the morning.

  1. Soak rice and mung beans overnight. Marinate seitan or meat.
  2. About 30 minutes of cooking. Boil beans and rice.
  3. About 30 minutes wrapping and packaging.
  4. Finally, an 8-12 hour boil in a big pot of water.

Ingredients needed:

  • Seitan or pork belly (optional), 4-8 oz
  • 5 c glutinous rice, lightly rinsed twice and soaked overnight
  • 2½ c dried slit mung beans, washed and soaked overnight
  • 2 shallots, thinly sliced
  • 2 leeks, use white part, thinly sliced
  • 2 t salt
  • 3 t black pepper
  • 1 t sugar
  • 2 t good soy sauce
  • 2 T fish sauce or 1 T mushroom powder
  • ½ c vegetable or peanut oil

Additional supplies:

  • Banana leaves (defrosted)
  • Twine, string, etc
  • Scissors
  • Plastic wrap
  • Aluminium foil
  • Cardboard and packing tape to make a mold. I used a soda box

Ingredient Prep:

  1. Cook rice with salt.
  2. Steam mung beans. Food-process them.
  3. Fry shallots and leeks in oil. Add seasonings.
  4. Remove from heat. Add the rest of the oil and mung beans. Mix thoroughly.

Making the cakes:

  1. Place the square cardboard mold on a sheet of plastic wrap.
  2. Put two cut banana leaves inside to form a little square pocket.
  3. In the pocket, layer ½ c rice, ¼ c mung beans mix, strips of meat or seitan, ¼ c mung beans, and ½ c rice.
  4. Fold the banana leaves over, and remove the mold. Close the plastic wrap to hold everything together.
  5. Wrap the plastic wrap in a layer of alumnium foil.
  6. Tie the foil shut with string.

Once you have all your cakes made, boil them at a low simmer for 8-12 hours. Your cakes are done.

They last weeks and stay pretty tasty. You can freeze them if you want them to last even longer.



30 days of learning, play, and newness

So I’ve decided on my next project! I’m going to spend a month learning new things. Unlike hack-a-day, where the focus was mostly on doing something every day, here I’m trying to cultivate a different attitude. So the following are all encouraged:

  • Being curious about stuff
  • Getting distracted
  • Having fun
  • New experiences
  • Being goofy, even if I don’t “learn” anything from goof experiences
  • Naps
  • Hanging with other people

And these are discouraged:

  • Completionism
  • “Grinding” through a nonfiction book I’m not that into
  • Rigorously writing up everything
  • TV and other mindless activities
  • (tentatively) reading?

Getting rid of mold

Take everything in this article with a cup of salt, I’m not even close to an expert.

Recently I’ve been itchy, so I’m treating a couple areas of my house for mold and mildew–the walls of my basement, and a new couch I got. I’ve been researching mold treatments. Some of them are clearly absolute nonsense.

never trust any cleaning procedure that involves mixing baking soda and vinegar

– za3k’s 42nd law

The sensical mold-killing strategies I’ve found boil down to “Remove moisture, so the mold doesn’t come back”, plus one of the following. I do not know which of these are effective. I also can’t guarantee the specific procedures I tried work.

Sunlight / UV lamp (UV light): I didn’t get good data about whether this works, but it makes some sense. The recommendation I got was 1-3 hours.
My attempt: None. I’d need a UV lamp, since I can’t easily get sunlight where I’m cleaning.

Bleach (oxidizer): Generally held to be pretty effective. Not good for fabrics.
My attempt: I tried it on my basement (dilute to about 0.15%, then pour or spray, scrub afterwards).
My attempt: I also added a little to laundry while I washed the couch cushions and my sheets.

Vinegar (acid): I would suspect vinegar is not very effective (several people claim mold can tolerate low pH better than high pH, and Drew Frye who does a lot of actual testing on boats claims that vinegar acts as food for the mold, helping it come back). OTOH I have anecdotal evidence that it works.
My attempt: None.

Concrobium (a base): This is a mix of trisodium phosphate (pH 12), sodium carbonate or “washing soda” (pH 11) and sodium bicarbonate or “baking soda” (pH 9). I suspect it works really well, because there’s a good explanation as to why it should. Store-bought concrobium is also quite expensive, so I’d make your own. I suspect you don’t need all three ingredients, because I think they’re doing the same thing.
My attempt: I sprayed spray-can concrobium on my couch, which covered maybe 1/6 of the couch with a $13 can. Plan to make some homemade to finish the job.
Edit: Muurkha advises that you can make sodium carbonate by boiling sodium bicarbonate for about an hour.

Clove oil (anti-microbial): Most people who recommend it have a bit of an anti-science attitude, which means they tend to give… silly specific advice. But there’s published research that it works, I just don’t know the best way to apply it, how long it works, or how it works. It seems possible that clove oil is a bit more species-specific than the other methods.
My attempt: None.

Mechanisms, as I understand them:

  • Sunlight and bleach should destroy mold and mold spores, by denaturing things.
  • Vinegar and concrobium should prevent mold growth by making an environment mold can’t grow in (wrong pH)
  • I have no idea how clove oil might work, but both applying the oil and vapor work.

I do not think high or low temperatures will work to kill molds generally, from my research.

The hardest part of this research is that I don’t have a large, visible mold patch. I’m just itchy. So don’t expect a report back about whether this stuff worked, honestly.