I needed to figure something out for my mom because she design one wall of the house and dose not have anything to put things on to raise them in the back so I thought of these.
Step 1: The First Cylinder
Make the first Cylinder radius of 7.5 cm and a height of 5 cm
Step 2: The Inside Bit
now make another Cylinder with a radius of 7 cm and a height of 5 cm
Step 3: Placement
Set both cylinders to 0,0,0. Now they should be inside each other.
Step 4: Copy
first copy the middle and make a copy. Then move the copy out of the way.
Step 5: Boolean
Select the biggest cylinder then go to compound objects and select Boolean and subtract the one in the middle. When you are done you will have a ring.
Step 6: Filling the Space
now select the copy and set it to 0,0,0. It should fill the space perfectly.
Step 7: Raising It
click on the center cylinder and raise it up 1 cm
Step 8: Now Putting Them Together
click on one of the cylinders and then go to the Boolean tool again but this time you will want to union them together. and now you have a 3D model of simple stacking blocks.