Otterness's later installations increasingly responded to and interacted with their physical and natural sites and environments. His 1999 "Feats of Strength" is a collection of his iconic whimsical bronze figures representing faculty and students interacting with pieces of the natural sandstone at Western Washington University. In a more urban setting (Claremont, California), Otterness's 2007 "Matriculated Nature" is embedded in the tiers of a fountain. Notably, it is one of his most intentionally thematic public artworks; Otterness's bronze figures are a series of vignettes to illustrate "the progression and evolution of knowledge and education, from early literacy to higher education," as they advance up the tiers of a fountain specially designed for the installation by architect Peter Tolkin.