4 jewels in a row. 8x8 lines

Lines 8x8 is a game play on 8x8 board with balls of eight different colors.
The goal is to connect 4 or more balls of the same color to a horizontal or vertical line.
The player can move one ball per turn, and the player may only move a ball to a particular place if there is a path
(linked set of vertical and horizontal empty cells) between the current position of the ball and the desired destination.
If the player does form such lines of at least four balls of the same color, the balls in those lines disappear,
and he gains one turn, i.e. he can move another ball.
If not, three new balls are added, and the game continues until the board is full.

Good brain trainer!