13．Have you ever tried the"Magic Cube"（魔方）？Pick up one of these cubes and you probably won't be able to （54）put it down．How hard can it be to rearrange the nine little（55）squares on each side of the cube？In fact，there are millions of possibilities!It has been over 30years since the cube first （56）hit the market!However，not many people know that it was used as a simple classroom（57）model at the beginning．
In 1974，Mr．Erno Rubik（58）invented the"Magic Cube"as he called it．He did this to help his students （59）understand difficult 3D concepts（概念）．This classroom example was quickly （60）turned into a popular toy．In 1979，ideal Toys started to sell it as"Rubic's Cube"．The invention quickly became a 1980s （61）cultural icon．
As time went by，the cube once（62）lost its attractive qualities．However，it made a comeback with the Internet．Now anyone can go online and find many videos that show ways to （63）solve the cube．Eric Akkersdijk of the Netherlands holds the world record now．he finished in just 7.08seconds．
