Placing objects is useful for many things. This can guide a ball when falling, helping a vehicle to circulate or a monster to fall into a box. These are examples of objects placement games.
In these games, you must start by using objects or forms that are available to you and place them on the stage. Then you trigger the arrival of a vehicle, you drop a ball or throw a monster, for example.
If your items are well placed, the ball should arrive at the desired point at the end of the level. If this is not the case, you must start over.