I have a guy that wants me to install landscape garden blocks (like pisa or something like that) around his lamp post and a bush (7ft diam area). He wants it like 3-4 (with the one in the ground) high. The problem is, i dont know how many blocks i'd need. Also, i have never done something like that, but he is a buddy that i can use to learn how to build something simple. 1. Is there a formula or something that i can use to calculate how many blocks i'd need? 2. Also, i need a place to learn how to construct it. Is manufacturer's website the best thing out there?