"tension - A tenuous balance maintained in an object between opposing formal or allegorical forces or elements often causing anxiety (from dissonance to angst to pain) or excitement (from the simply interesting to the utterly sublime). It embodies what is sometimes called edginess or frisson; and bears comparison to unity, harmony, and variety. Tension might be considered one of the principles of design."
http://www.artlex.com/ArtLex/T.html
The Symetry in the upper right is opposed by the placement of only one object in the lower left which is, additionally, out of alignment.
So, I'm a geek aficionado of semantics. Mea culpa.