% interface=en output=pdftex

\setupcolors[state=start]

\starttext 

\switchtobodyfont[10pt]

\setupbackgrounds[page][background={backgraphics,foreground}]

\startuniqueMPgraphic{rondje}
  path p;
  p := fullcircle scaled 2.5cm;
  fill p withcolor .95white;
  draw p withpen pencircle scaled 2pt withcolor .625red;
\stopuniqueMPgraphic

\startMPpositiongraphic{mypos:line}
  path pa, pb, pab ; numeric na, nb ;
  initialize_box(\MPpos{\MPvar{from}}) ;
  na := nxy ; pa := llxy..lrxy..urxy..ulxy..cycle ;
  initialize_box(\MPpos{\MPvar{to}}) ;
  nb := nxy ; pb := llxy..lrxy..urxy..ulxy..cycle ;
  if na=nb :
    pab := center pa -- center pb ;
    pab := pab cutbefore (pab intersectionpoint pa) ;
    pab := pab cutafter (pab intersectionpoint pb) ;
    pickup pencircle scaled 1pt ;
    draw pab withcolor .625yellow ;
    anchor_box(\MPanchor{\MPvar{from}}) ;
   fi ;
\stopMPpositiongraphic

\startMPpositiongraphic{mypos:circle}
  initialize_box(\MPpos{\MPvar{self}}) ;
  path p ;
  p := llxy..lrxy..urxy..ulxy..cycle ;
  pickup pencircle scaled 1pt ;
  fill p withcolor .800white ;
  draw p withcolor .625yellow ;
  anchor_box(\MPanchor{\MPvar{self}}) ;
\stopMPpositiongraphic

\defineoverlay[rondje][\uniqueMPgraphic{rondje}]

\setupframed [width=2.75cm, height=4cm, background=rondje, frame=off, offset=4pt]

\startcombination[6*2]
  {\framed{get\hpos{p1}{} state}} {}
  {\framed{concurrent updates}} {}
  {\framed{undo a program change}} {}
  {\framed{prevent unauthorized changes}} {}
  {\framed{associated changes}} {}
  {\framed{undo requirements changes}} {}
  {\framed{naming and \hpos{p2}{maintenance} state}} {}
  {\framed{version control}} {}
  {\framed{access control}} {}
  {\framed{change traceability}} {}
  {\framed{reconcilliation}} {}
  {\framed{modifications log}} {}
\stopcombination

Here is an example \hpos {foo}{of} anchors and layers. It works, \hpos {bar}{not} surprisingly, as advertised.

\defineoverlay[backgraphics][\positionoverlay{backgraphics}]

\startpositionoverlay{backgraphics}
  \setMPpositiongraphic{bar}{mypos:circle}
  \setMPpositiongraphic{foo}{mypos:circle}
  \setMPpositiongraphic{foo}{mypos:line}{to=bar}
  \setMPpositiongraphic{p1}{mypos:line}{to=p2}
\stoppositionoverlay

\stoptext

%finis