A nice picture.
From a nice site
Skillful Means of a Buddha ~ Nagarjuna
Just as the grammarian makes one study grammar,
A Buddha teaches according to the tolerance of his students;
Some he urges to refrain from sins, others to do good,
Some to rely on dualism, other on non-dualism;
And to some he teaches the profound,
The terrifying, the practice of enlightenment,
Whose essence is emptiness that is compassion.