In terms of gameplay, it's a list of positions, each a grid space apart. When you try to move, they are moved one at a time starting from the one closest to the player - if they try to move into an obstacle they get moved to another tile instead, which changes the direction the later sections will try to move. If there's still a collision after all of that then the entire move should be disallowed.
I can't comment on the graphical side of it.