{HEAD ~ Masks} can be used to form a pattern of crosslinked and non crosslinked regions on {TAIL ~ a surface} 
{ HEAD ~ Masks } can be used to form a pattern of crosslinked and non crosslinked regions on { TAIL ~ a surface }
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL