graue

    var fooString = "foo";
    var secondFooString = fooString;
    secondFooString;  // => "foo"
    
    fooString = "bar";
    secondFooString;  // => "foo"

    var firstArray = [1, 2, 3];
    var secondArray = firstArray;
    
    firstArray[0] = 100;
    firstArray;  // => [100, 2, 3]
    secondArray;  // => also [100, 2, 3]

    var firstVec = m.vector(1, 2, 3);
    var secondVec = firstVec;
    
    firstVec = m.assoc(firstVec, 0, 100);
    firstVec;  // => [100, 2, 3]
    secondVec;  // => still [1, 2, 3]