Ever noticed how a chest placed below a shulker box won't open?
Well it turns out you can still access the contents of the chest below without moving the shulker!
Simply open the shulker box above the chest, then exit the shulker box and quickly open the chest below. If you are fast, you will see that you can access the contents. However, you have to be quick enough, otherwise this won't work.
This is because when you open or close the shulker box, it changes shape and in doing so allows the chest lid below to open.