Blocks represent iconic features in most drawings. Sometimes you need to have two of those iconic features on top of each other. With 'Overlay Block' it's easy to place new blocks on top of existing blocks. All you have to do is make a selection of existing blocks. When you confirmed that selection you can choose which block you want to place on the same position. If you want you can use the scale and angle of the existing block and apply it to the new blocks.