how to make this creation, make your base a 11x5 block platform. then make a wall with levers 1 block apart from each other. on the other side of the wall 1 block under the levers put a block with redstone powder on it. then place a piston with slime blocks on it as in the picture (you will need 1.8 or later minecraft version). now im sure you could do the rest.
if this helped something, or was interesting. please comment and tell me what you thought.