## Texas Instruments 99/4A Computer

My uncle bought this computer, used it for a while, then gave it to my family when I was in high school (I think). It was our very first computer.
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## Treasure Hunt Thursday

Last Thursday, I bought three mainline Hot Wheels. One of them was a regular Treasure Hunt version of La Fasta (I blogged about it here) and the other two were in plastic bags with “collector’s booklets.” When I opened the bags, I was pleasantly surprised to find out that they were also Treasure Hunts. One was a regular Treasure Hunt version of 16 Angels. (A Super Treasure Hunt version of 16 Angels also exists.) The other was a regular Treasure Hunt version of Ratbomb. (A Super Treasure Hunt version of Ratbomb also exists.)

The “TH” symbol appears on the sides and at the back of the Ratbomb.

## La Fasta

Last Thursday, I passed by the toy store where I usually get Hot Wheels. It had been more than a week since I last passed by; there were some new models but I wasn’t that interested in them. One of the last items I looked at was this La Fasta. As you can see below, it is a regular Treasure Hunt.
As I was about to leave the shop, I saw a few Hot Wheels enclosed in plastic bags together with a “collector’s booklet.” The price (around 180 pesos) was almost twice the price of a mainline Hot Wheels (around 100 pesos).

I don’t think the booklet was worth 80 pesos, but I still looked at the bags because I had not seen some of the models before. The one on the left below had a metal base and seemed to have a metal body too because it was quite heavy. I bought it because I had never seen it before and because a mainline metal/metal is always a good buy.

The one on the right above had a symbol that looked like a “T” over an “H.” I had never seen this symbol before (usually a Super Treasure Hunt would have the letters written separately as “TH”). I bought it because there was a small chance it was indeed a Super Treasure Hunt. I’ll continue the story in a future blog post.

## The Extremist #1 (platinum edition)

In the early 1990’s, when comic book collecting became extremely popular, publishers would sometimes create special versions of certain issues as collector’s editions. Sometimes these had special colors, like gold or silver. Vertigo had what they called platinum editions.
Continue reading “The Extremist #1 (platinum edition)”

## ACM ICPC Bicol 2014

I was a problem setter and judge for the ACM ICPC Philippines 2014 National Programming Contest held last September 6, 2014 at the Ateneo de Naga University. (I was also a problem setter and judge in last year’s multi-provincial programming contest.)

There were 31 teams from 13 schools. The winning team was from Ateneo de Manila University. It solved all 10 problems in a little less than 2 hours. (The teams were given 5 hours.) The detailed results are here.

I provided two problems: “B” (Scrabble) and “H” (Boggle). My Scrabble problem was one of the easiest (26 teams answered it correctly) and my Boggle problem was one of the hardest (7 teams answered it correctly).

## First-order LSEs with constant coefficients: Repeated roots (continued)

In an earlier blog post, I showed the solution to a first-order linear system of two (ordinary) differential equations with constant coefficients for the case where the characteristic equation of the (constant coefficient) square matrix has repeated roots. In particular, I considered the system $\begin{array}{rcl}\frac{\mathrm{d}x}{\mathrm{d}t}&=&ax+by\\ \frac{\mathrm{d}y}{\mathrm{d}t}&=&cx+dy\\\end{array}$, where $a,b,c,d$ are real constants and $x,y,t$ are real variables, for the case where $(a-d)^2+4bc=0$ and $a\ne d$. Now I look at the case where $a=d$. Continue reading “First-order LSEs with constant coefficients: Repeated roots (continued)”

## Action Comics #1 CGC 9.0

I just learned through Fine Books & Collections that one of the Certified Guaranty Company‘s two highest graded copies of Action Comics #1 (the one with white pages) was sold on eBay last August 24, 2014 for US$3,207,852. (The other CGC 9.0 Action Comics #1 (with off-white pages) was sold in 2011 for US$ 2,161,000.)

I seriously doubt that there would be any other comic book more expensive than this one. (Click on the image to see where I got it from.)