# 人生的意義

（安：這個我不明白，昆蟲繁殖跟層壓式推銷有什麼關係呢？）

（安：好 insightful。我從來都沒有把 “昆蟲繁殖” 和 “層壓式推銷” 放在一起。）

— Me@2010.02.05

# 間書原理

Wikipedia
public domain image

《漫畫榮格》

— Me@2003-2004

2007.11.18 Sunday 2010.02.05 Friday (c) CHK2 ACHK

# Indicator function

In mathematics, an indicator function or a characteristic function is a function defined on a set X that indicates membership of an element in a subset A of X, having the value 1 for all elements of A and the value 0 for all elements of X not in A.

— Wikipedia on Indicator function

2010.02.05 Friday ACHK

# Essay

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I think the goal of an essay should be to discover surprising things.

— Paul Graham

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2010.02.05 Friday $ACHK$