This set is inpired from the sets Microcosmos and Nabokosmos. I
created it for people who never played Sokoban before. This set
contains some twin levels which allow you to learn progressively
this game by adding a box. An expert should solve it in less than
one hour. This set contains 2 levels "1box", 16 levels "2boxes"
and 22 levels "3boxes". (Aymeric du Peloux)