Сергей Соколов

var els = {
	input: document.getElementById('input'),
	check: document.getElementById('check'),
	links: document.getElementById('links'),
	link: document.createElement('a')
};

els.link.className = 'link';
els.link.href = '#';

els.check.addEventListener('click', function(){
	var a = els.link.cloneNode();
	a.innerText = els.input.value;
	els.input.value = '';
	els.links.appendChild(a);
});

_.extend = createAssigner(_.allKeys);

  var createAssigner = function(keysFunc, undefinedOnly) {
    return function(obj) {
      var length = arguments.length;
      if (length < 2 || obj == null) return obj;
      for (var index = 1; index < length; index++) {
        var source = arguments[index],
            keys = keysFunc(source),
            l = keys.length;
        for (var i = 0; i < l; i++) {
          var key = keys[i];
          if (!undefinedOnly || obj[key] === void 0) obj[key] = source[key];
        }
      }
      return obj;
    };
  };

  _.allKeys = function(obj) {
    if (!_.isObject(obj)) return [];
    var keys = [];
    for (var key in obj) keys.push(key);
    if (hasEnumBug) collectNonEnumProps(obj, keys);
    return keys;
  };

jQuery.extend = jQuery.fn.extend = function() {
	var options, name, src, copy, copyIsArray, clone,
		target = arguments[ 0 ] || {},
		i = 1,
		length = arguments.length,
		deep = false;

	// Handle a deep copy situation
	if ( typeof target === "boolean" ) {
		deep = target;

		// Skip the boolean and the target
		target = arguments[ i ] || {};
		i++;
	}

	// Handle case when target is a string or something (possible in deep copy)
	if ( typeof target !== "object" && !jQuery.isFunction( target ) ) {
		target = {};
	}

	// Extend jQuery itself if only one argument is passed
	if ( i === length ) {
		target = this;
		i--;
	}

	for ( ; i < length; i++ ) {

		// Only deal with non-null/undefined values
		if ( ( options = arguments[ i ] ) != null ) {

			// Extend the base object
			for ( name in options ) {
				src = target[ name ];
				copy = options[ name ];

				// Prevent never-ending loop
				if ( target === copy ) {
					continue;
				}

				// Recurse if we're merging plain objects or arrays
				if ( deep && copy && ( jQuery.isPlainObject( copy ) ||
					( copyIsArray = Array.isArray( copy ) ) ) ) {

					if ( copyIsArray ) {
						copyIsArray = false;
						clone = src && Array.isArray( src ) ? src : [];

					} else {
						clone = src && jQuery.isPlainObject( src ) ? src : {};
					}

					// Never move original objects, clone them
					target[ name ] = jQuery.extend( deep, clone, copy );

				// Don't bring in undefined values
				} else if ( copy !== undefined ) {
					target[ name ] = copy;
				}
			}
		}
	}

	// Return the modified object
	return target;
};

картинка треугольной сетки

1. округляются ли координаты до целых или до какой-то точности?
   
2. какой наибольший путь может проделать за один кадр точка?