class Vector{
   var length,angle;  // polar coordinates, radians
   fcn init(length,angle){  // angle in degrees
      self.length,self.angle = vm.arglist.apply("toFloat");
      self.angle=self.angle.toRad();
   }
   fcn toXY{ length.toRectangular(angle) }
   // math is done in place
   fcn __opAdd(vector){
      x1,y1:=toXY(); x2,y2:=vector.toXY();
      length,angle=(x1+x2).toPolar(y1+y2);
      self
   }
   fcn __opSub(vector){
      x1,y1:=toXY(); x2,y2:=vector.toXY();
      length,angle=(x1-x2).toPolar(y1-y2);
      self
   }
   fcn __opMul(len){ length*=len; self }
   fcn __opDiv(len){ length/=len; self }
   fcn print(msg=""){
#<<<
"Vector%s:
   Length: %f
   Angle:  %f\Ub0;
   X: %f
   Y: %f"
#<<<
      .fmt(msg,length,angle.toDeg(),length.toRectangular(angle).xplode())
      .println();
   }
   fcn toString{ "Vector(%f,%f\Ub0;)".fmt(length,angle.toDeg()) }
}