I love work of Barcelona-based artist Anna Taratiel (a.k.a. Ovni). Stemming from her background as both a graphic designer and a graffiti artist, her op-art style of work carries a lot of juxtapositions: dimensional/flat, primitive/mod, geometric/organic, sharp/sweet.
Below are a few of her installations.
Orbitas, 2008, at Rojo Artspace, Barcelona, Spain
In Between, 2008, in Lisbon, Portugal
Out of Order, 2008, at Kalpany Gallery, Milan, Italy