# Message #3589

From: Dan Karrasch <dkarrasch12@yahoo.com>

Subject: 9^4 Hypercube Solve

Date: Fri, 16 Dec 2016 18:50:59 +0000

Hi everyone,

I’m Dan, and this is my first time posting to a yahoo group, so hopefully I’m doing this right.

I recently solved the largest 4D cube to date, the 9x9. I solved it in 47,268 moves and completed the solve on 30 October 2016.

A little about myself: I’m 25, married, and I’m a mechanical engineer. No kids but 1 dog. I’ve been solving 3D Rubik’s cubes since I was a kid, being able to solve the 3x3, 4x4, and 5x5. Earlier this year I came across Mathologer’s youtube video about the 4D rubik’s cube and was immediately intrigued. I’m not as interested in the computer programming or mathematics side of 4D cubing, as much as I am interested in the concept of a 4D spatial reality that we may all be a part of but just can’t see because of our limited 3D senses. The 4D Rubik’s cube program allows me to play around in that possibility.

I naturally started with the 3x3 hypercube (solved: June 2016) and progressed to the 4x4 hypercube (July 2016) and 5x5 hypercube (Sept. 2016). At this point, I decided I wanted a real challenge. I noticed that the largest hypercube to be solved so far was the 8x8. I’ve never before had the chance to be the first in the world to accomplish something. So I decided that I wanted to take on the 9x9 hypercube.

Not only that, but I also noticed that the first 6x6 hypercube was solved in October 2010, 7x7-Oct. 2012, and 8x8-Oct. 2014. So not only was I determined to be the first to solve the 9x9, but I had to solve it by the end of October 2016 for the trend to continue (thanks OCD…), leaving me with just under 5 weeks to solve it. Note: This means the challenge is extended for someone to solve the 10x10 hypercube by October 2018!

About the solve: Like the 4x4 and 5x5 hypercubes, I started by building the inner cubes of each of the 8 cells. I started with yellow because it is the brightest and easiest to find. I found the yellow centerpiece and built a 3x3 cube around it inside the cell. I keep building it up until I have a 5x5 cube and a 7x7 cube of yellow inside the cell. Then I move onto the next color. This process took up the majority of the time, and I did this all with manual moves using intuition; no macros.

In the next phase, I built the faces of all of the cells (technically an edge? The pieces with 2 colors each). I followed a similar methodology; I would build a 3x3 square on the face, then a 5x5, then a 7x7. I repeated this process until all 8 cells were completely solved except for the edges and corners. I also got to this point using only intuition and manual moves. I did 21,000 manual moves before I did my first macro move.

Next I moved onto phase 3, which relied heavily on macros to solve the edges and corners. The setup moves feature was my best friend. There would be no way for me to remember all of the moves I did to set up each macro. The program automatically reverses my setup moves for me after the macro is finished. I would write my macros on a solved 9x9 hypercube to make sure they’re working as intended. Then I load the txt file to my solve session and just keep at it until the whole puzzle is solved. I did it with 1 day to spare!

My wife was VERY happy that I was done. As a joke, I told her that day that I was starting on the 10x10 hypercube. She wasn’t so amused. In all honesty, I’ll leave larger hypercubes for others to solve. I need to take a break for awhile, as I am still a part time grad student, and hypercubes have taken up the majority of my free time this summer and fall. It was a lot of fun and I’ll check back in every now and then to maybe tackle a new puzzle. Thanks to Melinda and team for creating and maintaining this program and the website! It’s been fun! -Dan