I've been wanting to build a pen for Cheerio, he is now 2 years old, and I think at this point he really needs one. I've been debating on how I should build it, I've been thinking of the kiddy pool idea, but I'm renting and my landlord would probably not want to look at an ugly plastic kiddy pool lol. I was thinking that maybe I could use wood for the siding because it looks more natural. Any advice or other ideas?