Lars Petrus facts for kids
Lars Erik Petrus (born November 4, 1960) is a famous Swedish speedcuber. He is known as a master and icon in the world of Rubik's Cube solving.
About Lars Petrus
Lars Petrus grew up in a place called Gammelstaden, near Luleå in Sweden.
He started speedcubing in the early 1980s. He learned how to solve the Rubik's Cube very fast during a summer when he had free time. In 1982, he became the best speedcuber in Sweden. He then competed at the first official Rubik's Cube World Championships. This big event was held in Budapest, Hungary. Lars finished an impressive fourth place overall.
Later, Lars shared his special way of solving the cube online. This method is called the Petrus system. It became quite popular with many speedcubers who were getting better at the cube. However, newer methods like ZZ, Roux, and CFOP are more common today. In November 2005, Lars Petrus won the "3x3x3 Fewest Moves" category at the World Championships. This competition was held in Lake Buena Vista, Florida, USA. He won a prize of US$500. He also competed in the 2006 International Rubik's Cube Competition in San Francisco. Since 1995, Lars has lived in the SF Bay Area, California, USA. He works there as a software developer.
The Lars Petrus System
The Petrus System was created as a different way to solve the Rubik's Cube. In the early 1980s, most people solved the cube layer by layer. Lars thought that when you solve one layer, it can make it harder to move other pieces. He wanted a method that gave him more freedom.
His idea was to solve the cube starting from one corner and building outwards. This way, he could move many parts of the cube freely as he went along. This method is often used when people try to solve the cube in the fewest possible moves.
How the Method Works
The Petrus system uses seven main steps to solve a Rubik's Cube:
- Build a 2x2x2 block (a small corner of the cube).
- Expand this block to a 2x2x3 without messing up the first part.
- Correct the edge orientation (EO). This means making sure the edges are facing the right way.
- Solve two complete layers of the cube.
- Permute the remaining corners (CP). This means putting the corners in their correct spots.
- Orient the remaining corners (CO). This means twisting the corners so they face the right way.
- Permute the final edges (EP). This means putting the last edges in their correct spots.
Lars Petrus invented three simple moves to help with the last three steps. He named these moves Niklas, Sune, and Allan.
Even though the Petrus method is very good on its own, people have made changes over the years. These changes help speedcubers solve the cube even faster. Many more moves have been added. Also, steps 5 and 6, or 6 and 7, are often combined to save time.
External links
- Rubik's World Championship 2005 - Official Results
- Solving Rubik's Cube for Speed by Lars Petrus
- Lars's Official Records: https://www.worldcubeassociation.org/persons/1982PETR01 - From the World Cube Association website
sv:Rubiks kub#Petrus-metoden
