Two reflections II (intersecting lines)

The JavaScript code

   var board = JXG.JSXGraph.initBoard('box', {boundingbox: [-5, 5, 5, -5], keepaspectratio:true}),
       A = board.create('point', [-2, -2], {withLabel:false}),
       B = board.create('point', [4, 0], {withLabel:false}),
       C = board.create('point', [-2, 2], {withLabel:false}),
       s = board.create('line',[A,B], {name:'s', withLabel:true}),
       t = board.create('line',[C,B], {name:'t', withLabel:true}),

       Ss = board.create('transform', [s], {type:'reflect'}),
       St = board.create('transform', [t], {type:'reflect'}),

       P1 = board.create('point', [0,-3], {name:'P_1', color:'green', size:8}),
       P2 = board.create('point', [P1, Ss], {name:'P_2', color:'green'}),
       P3 = board.create('point', [P2, St], {name:'P_3', color:'green', trace:true}),

       Q1 = board.create('point', [1,-4], {name:'Q_1', color:'blue', size:8}),
       Q2 = board.create('point', [Q1, Ss], {name:'Q_2', color:'blue'}),
       Q3 = board.create('point', [Q2, St], {name:'Q_3', color:'blue', trace:true}),

       l1 = board.create('line',[P1,Q1], {color:'black', strokeWidth:1, dash:2}),
       l2 = board.create('line',[P2,Q2], {color:'black', strokeWidth:1, dash:2}),
       l3 = board.create('line',[P3,Q3], {color:'black', strokeWidth:1, dash:2}),
     
       g1 = board.create('segment',[P1,P2], {color:'orange', strokeWidth:1, dash:3}),
       g2 = board.create('segment',[P2,P3], {color:'orange', strokeWidth:1, dash:3}),
       h1 = board.create('segment',[Q1,Q2], {color:'orange', strokeWidth:1, dash:3}),
       h2 = board.create('segment',[Q2,Q3], {color:'orange', strokeWidth:1, dash:3});