Objects simply stack up on top of one another quite gracefully.
The default stacking order says that the first item laid down will land on the bottom of the pile, and the last will be on top. In this example, image1 is on the bottom and image2 is on the top. Try letting a few objects overlap just slightly for some fascinating design effects. Let your light shine through Stacked objects can look great, if you plan properly, because your objects' native transparencies are respected. Letters can be seen through transparent .GIFs and vice versa.