Monday, September 19, 2011

Math in the Great Outdoors

Anyone who's ever studied Fibonacci numbers is now expecting a long ramble about pinecones, sunflower seeds, and flower petals. Sorry, out of luck. I'm sure you can find that sort of thing elsewhere. It's only taught to every elementary school student in the US school system. Okay, maybe not quite, but the number of times it was taught to me must make up for anyone out there who hasn't seen it.
In any case, what I'm actually writing about is doing math homework in the fresh, smoggy air of southern California. Under a tree, in my case, since the lack of humidity means that it's significantly cooler in the shade than the sun (a good 5-10 degrees isn't unheard of). That turned out to be a mistake. Look what happened!
Seriously, birds! Have some respect for the calculus!
For those who are a little slow on the uptake, that yellow stuff that's circled is the dropping of a kind (cheating!) bird who must have been checking out my work from above. If a bird ever turns in calculus homework that looks suspiciously like this, make sure to call him/her on plagiarism!

Sunday, September 11, 2011

Welcome to Debugging

I just spent around 4 hours trying to find a bug in my code, only to find a stinking rounding error. That I can't control. Yippee!
Somehow, DrRacket thinks that 12.0 x .0254 (number of meters in a foot) is 0.30479999999999996 rather than the correct 0.3048. It makes enough of these little errors over the course of a long string of computations that my tests are failing. Could anything be more frustrating? Okay, probably. But not right now.

Painters' Tape, part III

In continuing my ever-enduring quest to replace duct tape with painters' tape on the list of things that make the world go round, I have a third episode. My watch broke - I lost the pin that held the watch band to the watch. I'm currently looking into buying a new band or a new watch, but for the time being, I've fixed it up with good ol' painters' tape. Just to document this, here it is:


Next step in making painters' tape make the world go round: connect the earth to the sun with a giant string of painters' tape...this could be interesting...

Exploring Nature

Yesterday was an awesome day. All told, I spent around 6 hours being somehow physically active - walking, playing Ultimate, doing self-defense drills, and learning some Kendo. Awesome.
I spent an hour and a bit walking around the botanic gardens before rain (and a grumbling stomach) sent me back to campus. It was overcast all morning, which made it possible for me to really explore the lower gardens without overheating in half a second. It's quite the area. Also thanks to the overcast, I had approximately zero sense of direction, so I was very grateful for the giant 'EXIT' arrows painted on the trail at every intersection. Without those, I'd probably still be wandering around there completely lost.
Here are a few pictures from my explorations of nature:
This was the overcast lifting - it was just barely
possible to see the mountains to the north.

I loved this single flower. Unfortunately,
it was pretty far off the path, so I couldn't
get any closer.

Cute berries! Probably poisonous, but still cute!

Okay, look closely in the middle there. See that gray
blob? That's a squirrel hanging head-down trying to get
something off a branch that couldn't support its weight.
So much nature!

I loved the look of this tree. I'm not sure if it's dying
or just waiting for the wet season before it comes back
to life.
Okay, just a couple more pictures before I go back to frantically debugging my CS homework...
On my way to the bookstore to buy some Scotch tape on Thursday, I spotted a beautiful yellow and black butterfly. It was hanging out near a layer of wet leaves from the previous night's rain. I'm guessing that it was drinking. The fun thing was that it was still there around 40 minutes later as I was coming back to campus. It was just begging to have pictures taken of it. Here are the best of them:

Friday, September 9, 2011

Painters' Tape!

In my ever-enduring quest to use painters' tape to 'affix everything to everything,' I have moved from affixing posters (which are still hanging, by the way - definitely a new record for the map) to extension cords. I'll be the first to admit I was less-than-organized in my approach to this challenge, but here's a picture of how it ended up:
Note to my roommate: if you ever come into a predominantly blue room, I apologize in advance and point out that F&M did approve the use of painters' tape, and it's not a permanent alteration anyway...

Sunday, September 4, 2011

The Ultimate Engineering Challenge

I've had a very enjoyable weekend. I've been fairly productive, have played a little Ultimate, gone for two separate runs, and finished a lot of homework.
As a break from studying this evening, I decided to tackle the ultimate engineering challenge: hanging posters armed only with painters' tape. For those of you who don't know of the stuff, painters' tape is that blue masking-tape-like tape. It didn't take me long to find out why it's favored by painters - it doesn't stick to walls. No wonder, then, that it's the administration's sticky-material-of-choice for dorm rooms at Harvey Mudd. As an example of how bad it is at holding posters up, take a look at this first, naive attempt at hanging:

That didn't work. At all. By that I mean that it fell down within ten seconds of being stuck to the wall.  This stuff is that not sticky. This problem got me thinking. It stuck to the posters just fine, it just fell off the wall with hardly a second thought.
'Aha!' I thought, 'perhaps I can help it stick to the wall.' That I did. Here's my step-by-step method, in the hopes that it will help someone, somewhere, stick a poster to the wall using not-sticky tape.

Step 1: Long piece of tape
After getting rid of any dust on the wall with a damp rag, take a pretty long piece of tape and stick half of it to the wall. The remaining half should dangle off, on the side that forces of nature and evil will be fighting. That is, if you're fighting gravity, the top half should be dangling. If you're trying to prevent a corner from pulling away to the right, the left half should be dangling. If you're fighting anti-gravity...send me a blueprint for how you got that working and I'll share the Nobel prize with you.

Pretty simple so far.

Step 2: Prevent the dangling end from just dragging the rest of the tape off the wall with it.
This is done by putting another piece of tape perpendicular to the first, across it. Really, a picture will tell it best.
Then, crease the first piece so that there's a sharp edge right at the edge of the second piece. This will make the next few steps a lot easier. This setup on its own would work fairly well, but if your poster has any non-negligible weight, it might tear the second piece, drag the first off the wall, and fall down anyway. There are two weak points: on either side of the first piece, on the top edge of the second. We'll reinforce those next.

Step 3: Reinforce those weak points!
Next, you need to place two more pieces of tape parallel and right next to the first. These will reinforce the areas of the second piece most likely to tear. Again, a picture will tell it best.
Hooray! This, again, should work on its own, but it doesn't hurt to put one more piece of tape across those two to further reinforce the whole system.

Step 4: One more reinforcement
In this step, you place one last piece of tape parallel to the second piece, and across the third and fourth, to reinforce the weaker points there.
Hooray! You're done! Well, actually...you probably still want to hang your poster. If it's a width-wise or less-than-light poster, you probably want to make another one of these, just to be safe. It's a good idea to distribute the weight.

So...
Step 5: Repeat
Now, finally, you can hang your poster. Make sure the dangly bits are mostly where you want them to be, and then...

Step 6: Victory!

Step 7: Just to be safe
You've put so much work into this, it would be a shame for it to be less-than-utterly-perfect. Just to be safe, put a little roll of tape at each corner. These won't be supporting much weight, so the painters' tape will hold. Hopefully. Also, if your poster is really heavy, you might want to consider double-reinforcing the whole thing by repeating steps two through four.




I may or may not have spent upwards of an hour and a half doing this tonight. Most of that was for one poster. A giant (not quite full-size, fortunately, but pretty big) map of the world. I've historically had a lot of trouble getting this map to stay attached to a wall, so I really went all-out for it. There are 11 of these setups, all double-reinforced, behind the main body of the map, along with a roll at three of the corners and an additional sideways setup at one particularly persistent corner. Here is the proof that it has stayed put for at least long enough for me to get down off my bed and snap a picture of it:


I was also able to reuse the tape from my original failed attempt. At first, it went into the Pile of (Not-Quite-) Everlasting Doom:

Eventually, though, I found a better use for it.  These tiny little rolls of tape, while not strong enough to hold a poster, were more than enough for my mini-posters. Each of these was a picture on some date from a family calendar a few years ago. They work beautifully on my 'poster wall.'


All in all, a very enjoyable study break.