## Time Limits in Video Games

#### at 8:04 AM | Filed under mystery, video games

I've noticed that many newer video games don't seem to have time limits, but there's something about them that has been bugging me.

Think back to Super Mario Bros. The timer for each level would typically start with a few hundred "seconds," even though it always ticked down much faster than that. When the timer reached 100 or so, the music would speed up, causing a great deal of panic for the player. When the timer reached 0, Mario would die.

I understand that this just is a gameplay device to add some challenge to the game, but why does he die? By what mechanism is Mario killed when the time runs out?

Think back to Super Mario Bros. The timer for each level would typically start with a few hundred "seconds," even though it always ticked down much faster than that. When the timer reached 100 or so, the music would speed up, causing a great deal of panic for the player. When the timer reached 0, Mario would die.

I understand that this just is a gameplay device to add some challenge to the game, but why does he die? By what mechanism is Mario killed when the time runs out?

## TI-30XS Multiview Calculator

#### Saturday, May 23, 2009 at 10:32 AM | Filed under math, praise, reviews, technology

I was at Walgreens yesterday, looking for a new portable FM radio. Instead, I bought a calculator.

The TI-30XS Multiview Calculator, normally about $22, was on sale at $15, and it looked cool, so I got it. It has a neat feature called MathPrint mode, where it displays mathematical expressions in a more natural way (like how you write math on paper) rather than relying on a bunch of parentheses and junk.

On the left above, you can see a particularly complicated and useless expression as it would have to be typed on the TI-84 Plus Silver Edition. It has a lot of parentheses, and it's kinda hard to see what's going on. On the right is how the expression looks on the TI-30XS Multiview Calculator, with the MathPrint mode on. It's obviously a lot easier to see what's going on. (MathPrint can be turned off so that expressions can be typed in the classic mode.)

The TI-30XS also automatically simplifies fractions and roots. The first picture in this post has two examples of it doing this. On a different calculator, the answers would instead be displayed as decimals. There's a button you can simply press on the TI-30XS to convert these fractions or roots to decimals and vice-versa. It seems to be called the answer toggle button, and the button looks like this ◄ ►. There are two ways to input division: as a stacked fraction, or simply using the ÷ sign. The stacked fraction will try to give another fraction as an answer; the ÷ sign will yield a decimal answer.

You can see in the picture above that the calculator is also pretty smart with trigonometry. The TI-30X IIS on the left above calculated the sine of π as an ugly decimal. The TI-30XS is smarter than that, though. It displays the answer in exact terms using a fraction and a root, as it should. By pressing the answer toggle button, this can quickly be converted to a decimal, too.

So the TI-30XS seems to be able to do everything the TI-30X IIS can do, but there are still a few gripes I have with it. The answer toggle button is right above Enter (=), which is where plus usually is on TI calculators—the +, -, ×, and ÷ buttons are all moved one button up on the calculator, which takes a little getting used to. I keep pressing the answer toggle button when I mean to press plus.

Another issue is that there doesn't seem to be a way to wrap fractions or roots around expressions you have typed already. For a simple example, say you've typed 4, but then you realize you need to take the square root of 4. On the TI-30X IIS or the TI-84, you could move the cursor back in front of the 4 and insert a square root symbol. If you try to do that on the TI-30XS, though, it'll put a square root radical to the left of the 4, but there'll be a blank inside the radical, waiting for you to type in a number to go under it. The 4 will be to the right of the root, implying multiplication. I suppose you could work around this by raising 4 to the 1/2 power, but that seems imperfect.

Overall, it's a snazzy little calculator with a bunch more features I didn't even mention. The colors are bold and modern looking, but one of my friends said it looks like a child's toy. It's pretty thin (even more so without the cover slide case) and fits comfortably in the hands, and the buttons repsond well. (I think the TI-30X IIS is a bit too narrow to hold comfortably, and if you try to press a button before releasing the previous button, it'll ignore the second button press.) I would recommend to anyone looking for a cool calculator.

The TI-30XS Multiview Calculator, normally about $22, was on sale at $15, and it looked cool, so I got it. It has a neat feature called MathPrint mode, where it displays mathematical expressions in a more natural way (like how you write math on paper) rather than relying on a bunch of parentheses and junk.

On the left above, you can see a particularly complicated and useless expression as it would have to be typed on the TI-84 Plus Silver Edition. It has a lot of parentheses, and it's kinda hard to see what's going on. On the right is how the expression looks on the TI-30XS Multiview Calculator, with the MathPrint mode on. It's obviously a lot easier to see what's going on. (MathPrint can be turned off so that expressions can be typed in the classic mode.)

The TI-30XS also automatically simplifies fractions and roots. The first picture in this post has two examples of it doing this. On a different calculator, the answers would instead be displayed as decimals. There's a button you can simply press on the TI-30XS to convert these fractions or roots to decimals and vice-versa. It seems to be called the answer toggle button, and the button looks like this ◄ ►. There are two ways to input division: as a stacked fraction, or simply using the ÷ sign. The stacked fraction will try to give another fraction as an answer; the ÷ sign will yield a decimal answer.

You can see in the picture above that the calculator is also pretty smart with trigonometry. The TI-30X IIS on the left above calculated the sine of π as an ugly decimal. The TI-30XS is smarter than that, though. It displays the answer in exact terms using a fraction and a root, as it should. By pressing the answer toggle button, this can quickly be converted to a decimal, too.

So the TI-30XS seems to be able to do everything the TI-30X IIS can do, but there are still a few gripes I have with it. The answer toggle button is right above Enter (=), which is where plus usually is on TI calculators—the +, -, ×, and ÷ buttons are all moved one button up on the calculator, which takes a little getting used to. I keep pressing the answer toggle button when I mean to press plus.

Another issue is that there doesn't seem to be a way to wrap fractions or roots around expressions you have typed already. For a simple example, say you've typed 4, but then you realize you need to take the square root of 4. On the TI-30X IIS or the TI-84, you could move the cursor back in front of the 4 and insert a square root symbol. If you try to do that on the TI-30XS, though, it'll put a square root radical to the left of the 4, but there'll be a blank inside the radical, waiting for you to type in a number to go under it. The 4 will be to the right of the root, implying multiplication. I suppose you could work around this by raising 4 to the 1/2 power, but that seems imperfect.

Overall, it's a snazzy little calculator with a bunch more features I didn't even mention. The colors are bold and modern looking, but one of my friends said it looks like a child's toy. It's pretty thin (even more so without the cover slide case) and fits comfortably in the hands, and the buttons repsond well. (I think the TI-30X IIS is a bit too narrow to hold comfortably, and if you try to press a button before releasing the previous button, it'll ignore the second button press.) I would recommend to anyone looking for a cool calculator.

## 30-Minute Parking

#### Friday, May 22, 2009 at 8:08 PM | Filed under signs

This is a sign I saw in the Mukilteo Walgreens parking lot. What I find interesting is that this Walgreens has a one-hour photo lab, but they apparently insist that you leave before your pictures are done. Walgreens seems to be really serious about the 30-minute limit: they have a half dozen or so of these signs posted in the parking lot. The parking lot was mostly empty, so I don't see what they're worrying about.

## Ctrl + Backspace

#### Wednesday, May 6, 2009 at 11:58 AM | Filed under advice, technology

Being able to type flawlessly, without error, is a great skill to have, but for most people, the only way to decrease the number of errors is to also decrease the speed of typing. Thank goodness for the backspace key. With a single press, you can delete the last letter you typed.

The problem with this is that maybe you made a typo early in a word, but you didn't notice it until after you finished typing the entire word—for example, "spgahetti". You could backspace all the way back to the P and then start typing again: "aghetti". But that requires 7 backspace presses. You could move your hand to the mouse and highlight the errors, but it takes time to follow through with that.

One easy option is that you could simply press Ctrl + Backspace* and delete the last word entirely. "But then I have to type the whole word all over again!" you whine. Well, it isn't so bad. First of all, I find it hard to gain typing steam having to start typing in the middle of a word. Typing "aghetti" doesn't seem as natural as typing "spaghetti". Second, perhaps forcing yourself to retype the word will give you practice typing it correctly, particularly if it's a word you find yourself misspelling all the time.

After a while, it doesn't feel weird typing Ctrl + Backspace (especially if you use the left Ctrl key), and with practice, this is a very efficient and natural way to correct your typos.

*I use a Windows machine; I don't recall how this works on Macs, and I don't care to look it up. Also, some programs are stupid and for whatever reason don't support this, instead doing nothing or typing a dumb box instead.

The problem with this is that maybe you made a typo early in a word, but you didn't notice it until after you finished typing the entire word—for example, "spgahetti". You could backspace all the way back to the P and then start typing again: "aghetti". But that requires 7 backspace presses. You could move your hand to the mouse and highlight the errors, but it takes time to follow through with that.

One easy option is that you could simply press Ctrl + Backspace* and delete the last word entirely. "But then I have to type the whole word all over again!" you whine. Well, it isn't so bad. First of all, I find it hard to gain typing steam having to start typing in the middle of a word. Typing "aghetti" doesn't seem as natural as typing "spaghetti". Second, perhaps forcing yourself to retype the word will give you practice typing it correctly, particularly if it's a word you find yourself misspelling all the time.

After a while, it doesn't feel weird typing Ctrl + Backspace (especially if you use the left Ctrl key), and with practice, this is a very efficient and natural way to correct your typos.

*I use a Windows machine; I don't recall how this works on Macs, and I don't care to look it up. Also, some programs are stupid and for whatever reason don't support this, instead doing nothing or typing a dumb box instead.

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