adobe or concrete?

For the Pet Wall we are exploring brick (either adobe or concrete) as the primary module. After researching, debating, and talking with an expert in adobe construction we have decided that adobe would not be a reasonable material choice; concrete it is.

An ideal brick module will sponsor a variety of curves to take advantage of the site (existing tree, paths, etc), provide a surface to attach memorial/donor plaques to, and allow for future expansion. Here is an initial brick design: (click on images to enlarge)