Circum circles of subtriangles

Let ABC be a triangle and let the incircle intersect [math]BC[/math], [math]CA[/math], and [math]AB[/math] at [math]A'[/math], [math]B'[/math], and [math]C'[/math], respectively.

Let the circumcircles of [math]AB'C'[/math], [math]A'BC'[/math], and [math]A'B'C[/math] intersect the circumcircle of [math]ABC[/math] (apart from [math]A[/math], [math]B[/math], and [math]C[/math]) at [math]A''[/math], [math]B''[/math], and [math]C''[/math], respectively.

Then [math]A'A''[/math], [math]B'B''[/math], and [math]C'C''[/math] meet in one point, [math]P[/math].

The underlying JavaScript code

brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-1,4,12,-4], keepaspectratio:true});
brd.suspendUpdate();
p1 = brd.create'point', [0.5,-1.5] , {name:'A',fillColor:'red',strokeColor:'red'});
p2 = brd.create('point', [7.5,0.5] , {name:'B',fillColor:'red',strokeColor:'red'});
p3 = brd.create('point', [2,3] , {name:'C',fillColor:'red',strokeColor:'red'});
    
b1 = brd.create('line',['A','B'],{name:'',straightFirst:false,straightLast:false});
b2 = brd.create('line',['A','C'],{name:'',straightFirst:false,straightLast:false});
b3 = brd.create('line',['C','B'],{name:'',straightFirst:false,straightLast:false});
    
c1 = brd.create('circumcircle',['A','B','C'],{name:''});
c1[1].setProperty('strokeColor:#AAAAAA'); 
c1[0].hideElement(); // hide center of circle
    
l1 = brd.create('bisector',['B','A','C'],{name:'',visible:false}); // alpha
l2 = brd.create('bisector',['C','B','A'],{name:'',visible:false}); // beta
    
i1 = brd.create('intersection',[l1,l2,0],{name:'',visible:false});
pp1 = brd.create('perpendicularpoint',[i1,b1],{name:"C'",fillColor:'blue'});
pp2 = brd.create('perpendicularpoint',[i1,b2],{name:"B'",fillColor:'blue'});
pp3 = brd.create('perpendicularpoint',[i1,b3],{name:"A'",fillColor:'blue'});
    
c2 = brd.create('circumcircle',[pp1,pp2,pp3],{name:''});
c2[1].setProperty('strokeColor:#3CB371');
c2[0].hideElement();
    
c3 = brd.create('circumcircle',[p3,pp2,pp3],{name:''});
c3[1].setProperty('strokeColor:#FF8C00');
c3[0].hideElement();

c4 = brd.create('circumcircle',[p2,pp1,pp3],{name:''});
c4[1].setProperty('strokeColor:#FF8C00');
c4[0].hideElement();

c5 = brd.create('circumcircle',[p1,pp2,pp1],{name:''});
c5[1].setProperty('strokeColor:#FF8C00');
c5[0].hideElement();
    
i2 = brd.create('otherintersection',[c3[1],c1[1],p3],{name:"C''",fillColor:'blue'});
i3 = brd.create('otherintersection',[c4[1],c1[1],p2],{name:"B''",fillColor:'blue'});
i4 = brd.create('otherintersection',[c5[1],c1[1],p1],{name:"A''",fillColor:'blue'}); 

ll1 = brd.create('line',[i2,pp1],{name:'',straightFirst:false,straightLast:false,strokeColor:'#FF6347'});
ll2 = brd.create('line',[i3,pp2],{name:'',straightFirst:false,straightLast:false,strokeColor:'#FF6347'});
ll3 = brd.create('line',[i4,pp3],{name:'',straightFirst:false,straightLast:false,strokeColor:'#FF6347'});
    
i5 = brd.create('intersection',[ll1,ll2,0],{name:"P",fillColor:'#9932CC',strokeColor:'#9932CC'});
brd.unsuspendUpdate();