Italian artists Sten and Lex are in Maryland for Open Walls Baltimore where they just completed this large scale mural.
Their technique is to draw the pattern with pencil, stick the stencil on the wall and paint over it with a matrix which is then destroyed. The remains become part of the work and the stencil can never be reproduced.
If you stop by Baltimore, this one can be seen on Barclay street.
pics by Martha Cooper