function vec2(a,b){
	this.a = a
	this.b = b
}
vec2.prototype.magnitude = function(){
	return this.b-this.a
}
vec2.prototype.length = function(){
	return abs(this.b-this.a)
}
vec2.prototype.clone = function(){
	return new vec2(this.a, this.b)
}
vec2.prototype.abs = function(){
	if (this.b < this.a) {
		this.a = this.a ^ this.b
		this.b = this.a ^ this.b
		this.a = this.a ^ this.b
	}
	return this
}
vec2.prototype.midpoint = function(){
	return lerp(0.5, this.a, this.b)
}
vec2.prototype.add = function(n){
	this.a += n
	this.b += n
}
vec2.prototype.sub = function(n){
	this.a -= n
	this.b -= n
}
vec2.prototype.mul = function(n){
	this.a *= n
	this.b *= n
}
vec2.prototype.div = function(n){
	this.a /= n
	this.b /= n
}
vec2.prototype.contains = function(n){
	return this.a <= n && n <= this.b
}
// assumes (vec2)v falls to the right of (vec2)this
vec2.prototype.intersects = function(v){
  return (this.b > v.a) || (v.b > this.a)
}
vec2.prototype.union = function(v){
	if (this.intersects(v)) {
	  return new vec2( min(this.a,v.a), max(this.b, v.b) )
	}
}
vec2.prototype.intersection = function(v){
	if (this.intersects(v)) {
	  return new vec2( max(this.a,v.a), min(this.b, v.b) )
	}
}
vec2.prototype.toString = function(){
	return "[" + this.a + " " + this.b + "]"
}
vec2.prototype.quantize = function(n){
	n = n || 10
	this.a = quantize(this.a, n)
	this.b = quantize(this.b, n)
}