Relative paths can get quite complex. Here are a few examples, all without the resultant target directory displayed. Try to figure out where you'll end up after typing these commands:

$ cd /bin
$ cd ../usr/share/zoneinfo

$ cd /usr/X11R6/bin
$ cd ../lib/X11

$ cd /usr/bin
$ cd ../bin/../bin

Now, try them out and see if you got them right. :)