3-D Art Transforms Buildings-Graffiti and Sidewalk art

Plain vanilla buildings are often an eyesore, but leave it to the multi talented 3-D artists to transform them into the incredible optical marvels pictured here.
Other street objects transformed are circuit (electrical)boxes.
If these images are not inspiring enough, see streets themselves as canvasses, with the work of slightly naughty street artist, Relevo, the unbelievable works of Tracy Lee Stum, the Graffiti "tagging" of Daim, and sidewalk chalk is not kid's play here, Julian Beever transforms the pavement.
Not content with just the sidewalk, Felice Varini puts his spin on 3D optical illusions in unusual locations and no collective would be complete without a minimalist take, as these by Greg Brown.