Rubik's cube

I recalled that I was once immersed in Rubik's Cube. 

I started playing it when I was around 11 years old, and then finally reached 20 seconds to solve. 

if I do the memorization more, I think I can solve it in average 15 second or like that.

I'm not much motivated to go further because it's so complex and hard work.

he is Rubik Ernö, who invented the Rubik's cube.