CUBE_SIZE = 64
NUM_X = 20
NUM_Y = 12

#returns true if tractor can move to specified slot
def isValidMove(x, y):
    if x < 0 or y < 0:
        return False
    if x > NUM_X - 1 or y > NUM_Y - 1:
        return False
    return True

def getScreenWidth():
    return NUM_X * CUBE_SIZE

def getScreenHeihgt():
    return NUM_Y * CUBE_SIZE