Rubik's cube
https://plus.maths.org/content/taxonomy/term/1054
enHow hard is the Rubik's cube?
https://plus.maths.org/content/how-hard-rubiks-cube
<div class="field field-type-filefield field-field-abs-img">
<div class="field-items">
<div class="field-item odd">
<img class="imagefield imagefield-field_abs_img" width="100" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/abstractpics/5/30_jun_2011_-_1653/rubik_icon.jpg?1309449224" /> </div>
</div>
</div>
<div class="field field-type-text field-field-abs-txt">
<div class="field-items">
<div class="field-item odd">
<p>A Rubik's cube, you'll be pleased to hear, can always be solved in at most 20 moves, no matter how badly it was scrambled up to start with. Mathematicians have proved that that's true. But what if you're wrestling with a larger cube that has more than three little cubes in a row?</p>
</div>
</div>
</div>
<p>A Rubik's cube, you'll be pleased to hear, can always be solved in at most 20 moves, no matter how badly it was scrambled up to start with. Mathematicians have proved that that's true, and they've also proved that 20 is the best you can do: there are particularly horrible starting positions for which you do need 20 moves. (A move is any twist of any little face.) </p><p><a href="https://plus.maths.org/content/how-hard-rubiks-cube" target="_blank">read more</a></p>https://plus.maths.org/content/how-hard-rubiks-cube#commentsRubik's cubeMon, 04 Jul 2011 08:00:00 +0000mf3445513 at https://plus.maths.org/contentRubik success in twenty-six steps
https://plus.maths.org/content/rubik-success-twenty-six-steps
<div class="field field-type-filefield field-field-abs-img">
<div class="field-items">
<div class="field-item odd">
<img class="imagefield imagefield-field_abs_img" width="100" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/latestnews/may-aug07/rubik/icon.jpg?1180998000" /> </div>
</div>
</div>
<div class="field field-type-text field-field-abs-txt">
<div class="field-items">
<div class="field-item odd">
Computer scientists prove how long it should take you to solve Rubik's cube </div>
</div>
</div>
<div class="pub_date">05/06/2007</div>
<!-- plusimport --><br clear="all"></br>
<!-- END OF FILE: newinclude/news_header.html -->
<!-- FILE: include/rightfig.html -->
<div class="rightimage" style="width: 200px;"><img src="/latestnews/may-aug07/rubik/Scrambled.jpg" alt="A Rubik's cube" width="200" height="200" />
<p><em>Since this article was published the result has been improved to 20.</em></p><p><a href="https://plus.maths.org/content/rubik-success-twenty-six-steps" target="_blank">read more</a></p>https://plus.maths.org/content/rubik-success-twenty-six-steps#commentscombinatoricsgroup theorypermutationRubik's cubeMon, 04 Jun 2007 23:00:00 +0000plusadmin2554 at https://plus.maths.org/content