bugfix dual

Author: enkimute

examples/example_cga2d_basics.html

@@ -34,7 +34,7 @@
 
 // Define two circles, one by wedging 3 points, one directly.
   var C = ()=>p1^p2^p3,        // a function so it updates live.
-      D = circle(1,1,0.9);
+      D = circle(1,-1,0.9);
 
 // Define two lines, one directly, one by wedging two points and infinity.
   var X=line(0,1,0), Y=()=>p2^p3^ei;