Saturday, August 25, 2012

"Flipping Quarters" Solution

A couple of pieces of good news: First, in this post will be the answer to the problem I gave called Flipping Quarters; and second, I'll even work through the solution!

Friday, August 17, 2012

How I Got Blender

In a couple of my posts, you may notice some computer generated images or animations. They were created with Blender. In this post, I'll explain how I got it and started using it.

A long time ago, I wrote a BASIC program that drew a circle; the user would give the program a number, and it would draw a circle that size. There was a problem, though: the circle had a lot of holes in it. I solved the problem by filling the circle, but that was like cheating. I told my dad about the problem, and he showed me a book about graphics.

I looked through the book, but didn't find anything about my problem. I did find a section with nice, colorful computer-generated images, however - and some were so good they looked like photos! At one point, there was a series showing the construction of a photo-realistic image of a room, starting with the edges, then moving on to the surfaces, texturing, lighting, etc. Here's a similar series I made using Blender (but not photo-realistic):
Bump-Mapping, Reflections, Specularity, and Compositing
It looked so simple, I was hooked. I had to make my own computer-generated image that looked like a photo. I asked my dad to get me some software for 3D animations, so he searched on Google and found Blender. It looked like fun, and it was free, so we got it.

I followed some video tutorials I found on to make some nice images, and then I started making my own stuff. It was a lot of fun. I raved about it to my sister, but she just got sick of it and hated to even hear the name "Blender." Eventually, though, I convinced her to take a tutorial and make some balloons, and now she uses it to create images, like me. She uses it for art, but I also use it to show people how things work.

So that's how I got Blender. If you're interested in trying it out, just go to the download page on, and download it. Maybe you'll find it as fun and useful as I do.

Tuesday, August 7, 2012

Flipping Quarters

Here's an interesting puzzle involving chance:

A man in a park asks you to play a game with him. It's a form of gambling. To play, you must pay the man $5, then flip a coin repeatedly until you get heads. As soon as you get heads, you stop flipping. If you only flipped the quarter once, he'll give you $1. If you flipped it twice, you get $2. Three times, $4. Four times, $8. Each extra flip gets you twice as much money, so the longer it takes before you get tails, the more money you get.

Should you play, if you have a lot of time and the man will play as many games as you want? How much money, on average, would you gain (subtracting the $5 fee)?

I will give the solution in a later post.