drawing a container...

or may be not a container but a room.
A cube without ceiling, or a cylinder how can i do that?

This is what i am trying to do.

http://imageshack.us/photo/my-images/684/unledqza.png/

draw 5 solid cubes for each walls and floor? it is very hard to match their begining / ending this way.

so what is the correct way to do it?