text: var ArchContext = function(context, coordinate) {
  	this.ctx = context;
  	this.coordinate = coordinate;
  };
  
  ArchContext.prototype.draw = function(polar1, polar2) {
  	var from = this.coordinate.polarToCartesian(polar1[0], polar1[1], true),
  	    to = this.coordinate.polarToCartesian(polar2[0], polar2[1], true);
  	this.ctx.lineWidth = 1;
  	this.ctx.strokeStyle = "#F2805A";
  	this.ctx.beginPath();
  	this.ctx.moveTo(from[0], from[1]);
  	this.ctx.lineTo(to[0], to[1]);
  	this.ctx.closePath();
  	this.ctx.stroke();
  };
  