Old paint on canvas, as it ages, sometimes becomes transparent. When that happens it is possible, in some pictures, to see the original lines: a tree will show through a woman's dress, a child makes way for a dog, a large boat is no longer on an open sea. That is called pentimento because the painter 'repented,' changed his mind. Perhaps it would be as well to say that the old conception, replaced by a later choice, is a way of seeing and then seeing again.

最好的交易是你最有信心的交易。

Mathematics is not just about numbers, equations, computations, or algorithms: it is about understanding.

我不在乎过去，我在乎未来。