\VDDcpleadlinepart F:A(0,0)C(2,3.5):B(5,0) % calculate basepoint of perpendicular
\VDDdef K(0,-5)M(2,-1.5)L(5,-5)
\VDDcavg P:KL                 % calculate midpoint (average) of KL
\VDDcavg Q:LM
\VDDcavg R:MK
\VDDdcanvas1:1
  \VDDdlpolygon ABC
  \VDDdline BF                % draw BF
  \VDDlpointletter CFA        % label the point
  \VDDdperp CFB               % display symbol at F
  \VDDcdlpleadlinepart D:AB:C % do it all at once
  \VDDcdlpleadlinepart E:BC:A
  \VDDcppintersect H:AE:CD    % calculate intersection of AE en CD
  \VDDlpointletter BHE        % label H
  \VDDdlpolygon KLM
  \VDDdline MP
  \VDDlpointletter KPL
  \VDDdlinepartequal KPLP     % KP = LP
  \VDDdline KQ
  \VDDlpointletter LQM
  \VDDdlinepartequal LQMQ
  \VDDdline LR
  \VDDlpointletter MRK
  \VDDdlinepartequal MRKR
  \VDDcppintersect Z:MP:LR
  \VDDlpointletter KZP
\VDDdcanvasend
