duck

var moveDelay = 0.5f;
var gridSize = 1;
var x = 0;
var y = 0;

var moveX = 0;
var moveY = 0;

function Start() {
    Move();
}

function Move() {

    while (true) {
        yield WaitForSeconds(moveDelay);

        // code here is executed once per 'move delay'.

        (check keys and change direction here)


        x += moveX;
        y += moveY;

        transform.position = Vector3 ( x * gridSize, 0, y * gridSize);
    }
}