What does the Justified True Belief theory of knowledge say about what is necessary and sufficient for knowledge? Provide your own example of knowledge that meets these conditions.

Gettier

On Gettier, “Is Justified True Belief Knowledge?” What does the Justified True Belief theory of knowledge say about what is necessary and sufficient for knowledge? Provide your own example of knowledge that meets these conditions. Does Gettier argue that these conditions are unnecessary, insufficient, or both? Why so? Provide your own Gettier-style counter-example that demonstrates Gettier’s argument.