[5] In 1982, he became the national champion of Sweden, and went on to finish fourth overall at the first official Rubik's Cube World Championships held in Budapest, Hungary.
Petrus won the 3x3x3 Fewest Moves category at the 2005 World Championships held in November 2005 at Lake Buena Vista, Florida, USA claiming the US$500 prize.
In order for a layer-based solution to continue after the first layer had been constructed, the solved portion of the cube would have to be temporarily disassembled while the desired moves were made, then reassembled afterward.
While the method stands alone as an efficient system for solving the Rubik's Cube, many modifications have been made over the years to stay on the cutting edge of competitive speedcubing.
Many more algorithms have been added to shave seconds off the solution time, and steps 5+6 or 6+7 are often combined depending on the problems each case presents.