When you describe things it can be very useful to use shape vocabulary. Flat shapes such as square and circle are used as loanwords in a lot of languages but 3D shapes are not as common.
Click to see the graphic in a larger size.
You could describe a building by saying ‘It looks like a tube.’ However, sometimes you may want to sound more formal or technical. In this case, saying ‘It is cylindrical,’ would be better.
The grammar rule is:
It is a (shape name).
It is (shape adjective).
One thing that I didn’t include in the graphic was ‘cuboid’, which is like a cube but with two sets of equal sides (like a rectangular, irregular ‘cube’).
Examples
The server is the large cuboid computer. The small cubic thing is the router.
The difference between a wizard and a magician is wizards casts spells and wear conical hats whereas magicians perform tricks and wear cylindrical hats.