## ยง An elementary example of a thing that is not a vector

Consider the tripe (temperature, pressure, humidity) at a point. If we rotate
the picture by 60 degrees, the triple *does not change*.
Now consider the direction of wind at a point. If we rotate the picture by
60 degrees, the components of the wind vector *change* with our rotation.
Thus:
a vector is something that transforms like a vector.

To be more precise, I can phrase it as:
A vector iss (is and only is) something that transforms like a vector.

Generalization to tensors is left as an exercise for the reader.