Hi Liz, this pen is ok but you can't change the shape of it because of how it joins together i.e. you can't make it oblong or square.
After buying one of these I got another metal pen but this one had 3ft high panels (not 2ft) and they were pre-joined (rather than joined with metal stakes). It folds up neatly when not in use, it can be any shape you like and it was actually less expensive! I'll try and find one the same and post here!
I should have explained this. What Fluffers has said above is how my pen is. Except where it joins it isn't pre-joined or staked. They are metal poles that go through little holes to link it together. Very easy to take apart.
I bought mine from ebay for £50.00 so a lot more expensive. I saw one very similar to mine in the range for £30.00