This is a standard sliding block puzzle. Each piece is a different color. The pieces move orthogonally only, on the empty tan board, while the dark brown area is impassable. The puzzle is on the left half of the screen, while the right half shows the goal position. You move the pieces by clicking on any part (square cell) of the piece (left board only) and dragging it one cell in any unblocked orthogonal direction. Now the entire piece will move. You win when your puzzle position matches the goal position at the right.