function P(x, y) {
	this.x = x;
	this.y = y;
}
P.prototype.lineTo = function(g) {
	g.lineTo(this.x, this.y);
}
P.prototype.moveTo = function(g) {
	g.moveTo(this.x, this.y);
}
P.prototype.shift = function(dx, dy) {
	return new P(this.x + dx, this.y + dy);
}
P.prototype.toString = function() {
	return "("+this.x+","+this.y+")";
}