## Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

# Rolling blocks gather much interest

Best Answer superprismatic, 03 May 2013 - 09:22 PM

Spoiler for My best solution so far

Go to the full post

5 replies to this topic

### #1 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 22 April 2013 - 09:19 PM

Eight cubes are placed on a 3x3 grid with the center location vacant.

The top of each cube is distinguished by a certain color, say, as is the bottom, but by a different color.

The side faces do not matter.

Any adjacent cube may be "rolled" into the vacant location by giving it a 1/4 turn about a bottom edge.

By a series of such rotations, a configuration may be reached where the eight cubes are inverted,

and the center location is again vacant.

What is the minimum number of moves that accomplishes this?

All moves are by rotation.

A cube may not be slid into the vacant spot.

You can simulate this puzzle using eight dice.

Initially a "1" shows on the top faces; finally a "6" shows on the top faces.

To record a solution, U, D, L and R can be used for up, down, left and right.

The first three moves will alternate vertically and horizontally.

Therefore, you may begin your solution with URD.

• 0

Vidi vici veni.

### #2 TimeSpaceLightForce

TimeSpaceLightForce

Senior Member

• Members
• 705 posts
• Gender:Male

Posted 23 April 2013 - 04:10 AM

I've seen one in a Escape the Room Game. Since we are just playing for the least rolls it might be helpful if we use the mini program

http://www.jaapsch.n...t/eightcubj.htm .Enjoy ..Don't press SOLVE.

• 0

### #3 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 23 April 2013 - 08:50 AM

I've seen one in a Escape the Room Game. Since we are just playing for the least rolls it might be helpful if we use the mini program
http://www.jaapsch.n...t/eightcubj.htm .Enjoy ..Don't press SOLVE.

Great.
Start out all white, end up all yellow. Fewest moves.
• 0

Vidi vici veni.

### #4 superprismatic

superprismatic

Not just Prismatic

• Moderator
• 1281 posts
• Gender:Male

Posted 03 May 2013 - 09:22 PM   Best Answer

Spoiler for My best solution so far

• 0

### #5 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 05 May 2013 - 10:56 PM

Spoiler for My best solution so far

Good solve.
As far as I know this is the minimum number of moves (proven by simulation.)
• 0

Vidi vici veni.

### #6 superprismatic

superprismatic

Not just Prismatic

• Moderator
• 1281 posts
• Gender:Male

Posted 05 May 2013 - 11:40 PM

I solved it with by exhaustion over all possible paths of moves less than 38.

I saw that Martin Gardner's column of 1975 had a 38-move solution, so I started there.

• 0

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users