Super-killing-time puzzle All the 50 pages are clearable?
It is an application which is made quickly at the free vacant time and which chooses and erases crystal.
The crystal of the color specified by the top arrow in the colorful crystal on a par with middle of the screen is only erased in order. However, the crystal of the four directions of the erased crystal will be discolored. The order of discoloration is "blue -> red -> purple -> green -> water -> yellow -> white." White crystal is not discolored.
It will improve, if the crystal on a screen can all be erased well! You are [ whether all the 50 pages are clearable and ] ?!.