Laser art part 2: Mars

[Part 1 here]


Let me tell you, friends, this project was a big one, and I made it bigger by making more dumb mistakes. First, I found a topographical map of Mars that was made in 1993. It was only after tracing the entire thing that I learned the first of two important facts: we didn’t know much at all about Mars until 1997 when the Mars Global Surveyor arrived; every map made before that point was based on data gathered in the Mariner missions in the 1960s.


The newer maps of Mars measured elevation in a color gradient rather than in convenient lines at each kilometer mark. Rather than start from scratch, I layered this map over the one I had made and started nudging my lines around. Eventually I got it looking pretty accurate, except there was one weird thing about the two maps. The elevations didn’t line up.

Here I learned the second important fact about Mars: since Mars doesn’t have a sea, scientists had to choose an elevation to use as “sea level,” which is where you would define 0 on a topographical map. Up until 2001, they measured sea level by atmospheric pressure.

But then in 2001 the Mars Orbiter Laser Altimeter arrived and gave them more specific data, and they decided instead to base sea level on the equipotential surface. So in other words, not only was the map I made only vaguely accurate in terms of landmarks, it also started counting up from 0 at a different height.

Mars vector

I don’t know how many hours I put into just making the file. Dozens, anyway. Then I had to split the whole map into three sections so it would fit in the laser cutter. I used twelve sheets of 12″ square birch plywood. You can buy this in bulk from Michael’s, so the whole thing ended up costing me only about $22.

I paid attention to the grain of the wood this time and I masked everything first so I wouldn’t get smoke stains on everything. I even lightly scored lines on each layer to show where the next layer was supposed to go, so I could align things exactly and so I wouldn’t end up with a bunch of random bits and no idea where they were supposed to go. I still ended up with a bunch of random bits, but fewer than I would have.


It was in assembling the thing that I learned a final important fact, not about Mars but about topography in general: when you’re making a topographic map on birch plywood that is 1/8″ thick, and each level of elevation on the map is 1 kilometer of height, that means 1/8″ up and down = 1 kilometer. But if the map is 27″ wide and the planet has a circumference of 21,343 km, then 1/8″ left and right = 98.8 kilometers. Because of this discrepancy, everything gets stretched out to look much taller than it is.

If I were making the map completely accurate, then each layer of this 27″ wide map should have been .001″ tall (or about the width of a human hair). The entire 25 kilometer height of Olympus Mons would end up being 1/32″ tall (or about the thickness of the lead in a mechanical pencil). But that makes for a very boring topographical map, so I didn’t do it that way.

The end result is that Olympus Mons ended up looking VERY TALL.


I took out every other layer of all of the mountains to get them down to a more reasonable looking height, since I didn’t want any of them sticking up three inches over the rest of the map. I think the end result looks quite nice.

Mars last

All I have left to do is mount the three parts on a single sheet of plywood and then maybe frame it or something. Maybe I’ll hang it on my wall, if it’s not too heavy. I’m already thinking of what to make next. What’s bigger than a planet?



Laser art part 1: Cape Cod Bay


Last year I got my hands on a Glowforge Pro laser cutter. It’s not mine (it may be cheap for a laser cutter but it’s not actually CHEAP) but I needed to learn how to use it, and what better way to do that than try my hand at making some art.

Glowforge has a whole catalog of projects you can make, as well as forums full of people showing off their own projects, but I actually got my inspiration from seeing this gorgeous thing and deciding I could make one just like it. Because, you know, I wanted to start simple.


You can find topographical maps of just about anywhere online. The US Geological Survey has a ton of maps, both current and historical, and you can download all of them for free. You can also find bathymetric maps (that’s underwater topography) of just about any significant body of water. Yes, all of those links are US-centric, but I’m sure you can find similar repositories for elsewhere in the world. I haven’t done anything outside of the US yet. …Well, actually I have, but I’ll get to that in a bit.


Actually cutting out the image and assembling it is the easy part. It’s making the file to cut out that takes a billion hours of tedious work. If you’re extremely lucky, you’ll find a PDF of a map that’s already mostly in vector format, although even those take many hours of cleanup before they’re usable. Mostly you just find a flat image and you have to trace it. For hours. And hours.

Eventually you start to fudge things because seriously, no one is going to look that closely and no one really knows where Dead Neck is or how many shipwrecks there really are off Provincetown. But it’s really cool to know that every single sandbar and pile of rocks off the coast has a name.


I made SO MANY MISTAKES on this project. For one thing, the size of my project was too large to do in one go on the laser, so I had to split each layer into two halves, and I didn’t figure out a good way of doing that until after I’d finished the whole project, so there are a lot of uneven gaps and things not lining up correctly.

I didn’t notice that the grain of the wood was going in different directions until it was far too late, although in my defense there wasn’t much I could have done about that even if I had noticed ahead of time, since the wood was pre-cut into 16×20″ rectangles so I couldn’t rotate them.

Also, I hadn’t done any tests ahead of time to see what settings I would need to cut through the wood, so some places got scorched and other places didn’t cut all the way through and I had to hack at them with a knife.


When the whole thing comes together, though, it looks amazing. You can make anything look good when lasers are involved. I like the effect of the smoke marks, although you can avoid that with masking tape.


I did this entire project last May. Around December I decided to try my hand at it again using the stuff I’d learned, so I made two small town maps for family members. And then I thought… well, what next? What can I make for myself that will look just as cool as Cape Cod Bay?

The answer, it turns out, was Mars.

[Part 2 coming soon!]

My Kitty, RIP

skit small

We got Skittles in October of 1998 from a family who was overrun with cats. We actually intended to get a different cat, but when we went to visit, the cat we had picked out was skittish and unfriendly, and we already had one of those. Then Skittles came bouncing into the room with a handful of other kittens, and she was the one we went with.

She was named Pumpkin at the time, but our other cat was named Snickers for reasons I can’t remember, so we renamed her. She was as different from Snickers as she could possibly have been: she loved people and loved having her head scratched and sitting on people’s laps. She would start purring when I walked into the room. Later, she was the chunky, ungraceful one while Snickers was lithe and could leap six vertical feet in the air. The only thing the two cats had in common was that they hated each other.

She taught Snickers how to make eye contact with us when she wanted something, which was a skill Snickers never would have figured out on her own. She also taught Snickers how to purr, although Snickers never got the hang of that very well. She learned how to open cupboards and was adept at prying the lid off the can of treats. She was fiercely territorial and would fight any animal that strayed into our yard, including the poor golden retriever next door who just wanted to be friends.

Once, when she was still quite young, she had an unfortunate accident with our garage door. She liked sitting on top of the minivan while it was in the garage, and apparently one day, while the garage door was open, she climbed from the roof of the minivan to the shelf made by the garage door. When I hit the button to close the door, she panicked and tried to escape, but got her foot caught in between the slats and ended up dangling by her hind leg from the middle of the closed garage door. It was only luck that I heard her crying and went out to investigate. It was also luck that she didn’t break her leg. Frankly I’m not sure how she managed that one. Decades later, she still was terrified of the garage door, although I don’t think she remembered why.

Another time, she cheerily went to greet a neighbor of ours who was watering his plants. She was so friendly that he decided this meant she was rabid, so he sprayed her with the hose. She fled into his garage (again with the garages) and, not knowing she was in there, he shut the door. We searched for her for three days. Finally the neighbor opened his garage door and found her. She hissed at him and he phoned us, saying she was rabid and we should get her before he called animal control. Of course she was more than happy to see us and gratefully went home.

In later years, she tormented Snickers. Rather than wake us up to get her breakfast, she would settled into Snickers’s bed when Snickers got up in the night to pee. Poor Snickers, who by this point was suffering dementia and arthritis, would wander the halls meowing, begging for help at evicting the other cat from her bed. Skittles didn’t particularly care about the bed; she just wanted someone else to get her breakfast.

When Snickers died at age 19, a dramatic change came over Skittles. Maybe she had considered Snickers company, even if she had hated her. She was suddenly lonely. It became apparent that at some point she had gone mostly deaf and mostly blind, and was also suffering from arthritis. The other cat had been so old and bedraggled that Skittles seemed young by comparison, but now it was clear that Skittles was almost 18 years old. I started letting her sleep in my bed, even though I was allergic, because I felt bad for her. Claritin became my friend.

She became desperately clingy, which is apparently something that happens to cats when they get very old. If I was home, she needed to be within three feet of me. Ideally she would be on my lap, but she would settle for my keyboard. I set up a cardboard box on my desk so she could sleep on it and not bother me. When I got my standing desk, I had to drag the desk chair next to me so she could sleep on that while I worked. If I went away for a weekend or, worse, when I went to Ireland for a month, she got deeply depressed and stopped eating.

She also got very talkative. She would meow when she walked into a room, or when she saw me for the first time in a while, or if I touched her. Sometimes, when she was lazy and didn’t feel like making a full meow, she would kind of huff and nod her head at me. She would still start purring at the sight of me.

In March, we took her to the vet because she had stopped eating. By this point she was down to 6 pounds. At her prime, she had been 12 pounds. It turned out that she had a tumor underneath her tongue that was making it hard for her to eat. Since she hadn’t had it in December at her last check up, it was clear that it was growing fast. The vet gave her 1-3 months to live.

It seemed impossible. She was still so vital! She was happy! She took her painkillers without a fuss. Surely she would last longer than that. And for the first two months, she seemed fine.

Three weeks ago, she stopped grooming herself and stopped being able to pick up food. She could only eat if you hand-fed her tiny bits that she could swallow without chewing. She straight up refused to take her painkiller no matter how well we hid it.

Two weeks ago, we decided it was time. We gave her all the treats we could over the next two days, and on that Thursday we took her to the vet. Her tumor had grown so much she couldn’t use her tongue, and she was down to 5 lbs. It would have been cruel to make her continue on.

It was so hard. I can’t tell you how hard it was. I’m 32, and she had been around since I was 13. She had been my constant companion for the last couple years. We knew each other so well that we could practically read each others’ minds. Even on Thursday she curled up happily in the crook of my arm to nap. I know she would have soldiered on to the bitter end because she had no other choice, and I felt partly as if I had betrayed her by making that decision for her, but I also know that she probably only had another week or two, or at most a month, before the end was inevitable, and it would have only gotten worse. I hate that it had to happen, but it had to happen. I will miss her.

I love you, my darling. Good night.

Art of the Day: Barley

I hadn't noticed how similar this pose is to the drawing I did of my cat until just now.
I hadn’t noticed how similar this pose is to the drawing I did of my cat until just now.

I’m dog- and cat-sitting for my brother this week, while he and his girlfriend travel to San Diego. The cat, Midnight, is sweet but shy and likes to keep her distance from the dog, who’s a little too energetic for her. The dog, Barley, desperately wants to SNIFF HER FACE OH MY GOD WHAT DO HER EYES SMELL LIKE I HAVE TO KNOW RIGHT NOW. So that’s going well.

Art of the Day: My kitty, RIP

Snickers, 1996-2015. Digital painting in Photoshop with Wacom tablet.

Nineteen-ish years ago, when my family was moving houses, my parents decided that we needed a new cat. My mother and I were both allergic, but we adored cats, so we decided it was worth it. At the farm supply store in town, they were selling the kittens of a feral cat. We bought a quiet, pretty one and named her Snickers.

Of course, she was feral, and we hadn’t realized what that would mean until we got her home. She didn’t like people. She didn’t like being touched. She didn’t purr. She didn’t realize that we were actual living creatures. The bare ankles she attacked in the hallways at night weren’t connected to the same person as the hands that tried to pet her or give her food. Once, I was holding her while feeding her a meatball, and when someone went to pet her, she bit me because she thought we wanted to steal her food. We all ended up having to get tetanus shots after various attacks.

A year or so later, we adopted another kitten, this one a pudgy, friendly cat who loved people and would start purring loudly the moment you entered the room she was in. That cat we named Skittles. The two cats hated each other from the start, and would fight regularly. The only times they would ever tolerate each other’s proximity was when the doorbell would ring and they’d both run to the top of the stairs to stare at the door in wide-eyed unease. They constantly vied for dominance, but Snickers always ended up as the alpha cat.

Still, over the years Snickers learned a lot from Skittles. She learned how to look us in the eye to get our attention and lead us to the door or her empty water dish when she wanted something. She learned how to meow at the window when she wanted to come inside, although it was the tiniest little meow you’d ever heard. She learned how to purr, although it was very hard to tell when she was purring because it was so quiet that you’d need to put your ear up to her head to hear it, and no one ever wanted to get that close to her.

She had a tear duct problem and would cry blood like a Bond villain. One year, we gave her off-brand flea medication and it gave her scar tissue in her other eye that pinned one side of her pupil open, giving her the weird triangular eye that you can see in the picture above.

In her later years, she mellowed. When she was outdoors and we drove in the driveway, she’d come running over to greet us and rub against our legs. She loved my dad because he gave her snacks, so she followed him everywhere in the house and would sleep at the foot of his bed. She only ever purred when my dad was around.

Once, she climbed onto my mother’s lap while my mom was sitting in the sun and settled down for a nap. My mother was frozen in anxiety, too afraid to move in case Snickers decided to attack. Eventually we lured Snickers away with some turkey. It was the only time she ever did it.

Eventually she even decided she liked getting her head scratched. If you held out your hand to her, she’d sniff it carefully, then duck her head under your hand to give you the hint.

In the last year or two, she started to show her age. She had arthritis in her tail and could no longer sit. The process of going from standing to laying down was a slow, painful maneuver that took over five minutes. She could no longer groom herself, and hated being brushed, so her fur got matted and tangled. She developed kitty dementia and forgot where her water dish or food bowls were, and sometimes got lost outside and needed to be guided home. She forgot how to use a litter box. She had terrible balance and weak hind legs and would fall over at the slightest breeze.

Wednesday, she started having trouble eating. We could have had the vet examine her and see what was wrong, but it would stress her out too much and the odds were good that there was nothing we could do to improve her quality of life. We brought her to the vet last night and got a chance to say goodbye to her before she was put to sleep.

She was a difficult cat to love, but I wouldn’t trade her for the world. Though it was hard to tell at times, I think she had a happy life. It was certainly a long one. She was around for more than half my life, and I honestly can’t imagine this house without her. I’ll miss her.

Good night, kitty. I love you.