From: Xinding Sun
Subject: the nine dots
Date: 2001-01-09

You can connect them without leaving the rectangle in four straight lines.

Suppose the rectangle is

  A B C
D E F
G H I

The solution is A->B-C->F->E->D->E->F->I->H->G.

Note that you can draw this without leaving the hand from the paper, but you have to draw on the line DEF twice. But the result is four straight lines.

Xinding Sun

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