@options;

@figure;
  gogeometry = texte( 1.6 , -7.6 ,"Antonio Gutierrez. www.gogeometry.com")  { rougefonce , dec1 , car-3 };
  click = texte( -7.2 , -7.6 ,"Click this button to start/stop the animation")  { rougefonce , dec2 , car-3 };
  A = point( -4.97 , -4.7 )  { croix0 , (-0.03,-0.03) , i };
  N2an = point( -3.03 , 4.2 )  { i };
  N1an = point( -4.2 , 3 )  { i };
  ceN2N1 = cercle( N2an , N1an )  { i };
  xx = reel( 353.5 , 0 , 360 , 2.5 )  { oscille , (7.67,-8) , i };
  var yy = 180*cos(xx)+150 { 328.842934021786 };
  B = pointsur( ceN2N1 , yy )  { rond2 , (-0.4,-0.97) , i };
  C = point( 3.23 , 2.7 )  { (-0.13,-0.94) , i };
  dAC = droite( A , C )  { bleuocean , 7 , sansnom };
  perpBsAC = perpendiculaire( B , dAC )  { stop , bleuocean , 7 , sansnom };
  D = pointsur( perpBsAC , -11.08 );
  dAB = droite( A , B )  { grisfonce , 7 , sansnom };
  dAD = droite( A , D )  { grisfonce , 7 , sansnom };
  dCD = droite( C , D )  { grisfonce , 7 , sansnom };
  dBC = droite( B , C )  { grisfonce , 7 , sansnom };
  polyABCD = polygone( A , B , C , D  )  { jaune , plein80 };
  sAB = segment( A , B )  { noir , 3 };
  sBC = segment( B , C )  { noir , 3 };
  sCD = segment( C , D )  { noir , 3 };
  A1 = texte( A ,"A")  { (-0.13,0) , dec2 };
  B1 = texte( B ,"B")  { (-0.26,-0.93) , dec2 };
  C1 = texte( C ,"C")  { (-0.13,-1) , dec2 };
  sDA = segment( D , A )  { stop , noir , 3 };
  sAC = segment( A , C )  { bleuocean , 2 };
  Q = pointsur( perpBsAC , 1.33 )  { i };
  Q1 = texte( Q ,"AC perpendicular to BD")  { (-0.1,-0.74) , dec2 , car-3 };
  sBD = segment( B , D )  { stop , bleuocean , 2 };
  E = milieu( A , B )  { rond3 , (-0.67,-0.6) };
  E2 = texte( E ,"Midpoint of AB:")  { (-3.3,-0.44) , dec2 , car-3 };
  E1 = milieu( A , B )  { stop , \ , croix0 , sansnom };
  F = milieu( B , C )  { rond3 , (0.1,-0.83) };
  F1 = milieu( B , C )  { stop , / , croix0 , sansnom };
  G = milieu( C , D )  { rond3 , (0.13,-0.5) };
  G1 = milieu( C , D )  { stop , // , croix0 , sansnom };
  H = milieu( D , A )  { rond3 , (-0.67,0.03) };
  H1 = milieu( D , A )  { stop , /// , croix0 , sansnom };
  R = pointsur( polyEFGH , 3.55 )  { i };
  R1 = texte( R ,"EFGH: rectangle of Varignon")  { vert , (-4.6,-0.54) , dec2 , car-3 };
  polyEFGH = polygone( E , F , G , H  )  { vertclair , plein10 };
  perpEdCD = perpendiculaire( E , dCD )  { vert , sansnom , i };
  E' = intersection( perpEdCD , dCD )  { vert , rond3 , (0.36,-0.3) };
  sEE' = segment( E , E' )  { vert , 2 };
  E'1 = texte( E' ,"EE'£perp£CD")  { vert , (0.87,-0.11) , dec2 , car-3 };
  angleEE'D = angle( E , E' , D )  { stop , vert };
  perpFdAD = perpendiculaire( F , dAD )  { vert , sansnom , i };
  F' = intersection( perpFdAD , dAD )  { vert , rond3 };
  sFF' = segment( F , F' )  { vert , 2 };
  angleFF'D = angle( F , F' , D )  { stop , vert };
  perpGdAB = perpendiculaire( G , dAB )  { vert , sansnom , i };
  G' = intersection( dAB , perpGdAB )  { vert , rond3 , (-0.6,-0.8) };
  sGG' = segment( G , G' )  { vert , 2 };
  angleGG'B = angle( G , G' , B )  { stop , vert };
  perpHdBC = perpendiculaire( H , dBC )  { vert , sansnom , i };
  H' = intersection( perpHdBC , dBC )  { vert , rond3 , (0.06,-0.76) };
  sHH' = segment( H , H' )  { vert , 2 };
  angleHH'B = angle( H , H' , B )  { stop , vert };
  sEG = segment( E , G )  { i };
  sFH = segment( F , H )  { i };
  O = intersection( sEG , sFH )  { rouge , rond3 };
  ceOG = cercle( O , G )  { rouge , 2 };
  P = pointsur( ceOG , 154.87 )  { i };
  P11 = texte( P ,"Eight-Point Circle")  { rouge , (-3,-0.67) , dec2 , car-3 };

@config;

boutons=animation;