Four Knights

The applet below presents an old puzzle. The board is a 3x3 part of the chessboard. The only allowed move is to drag a knight to another square following the usual chess rules. Of course, no two knights may occupy the same square. The purpose of the puzzle is to swap red and blue knights.

On the right, 8 squares are arranged in a sequence. There is correspondence between the squares and knights on the two halves of the display. The sooner you grasp this relationship, the easier it will be for you to solve the puzzle.

This applet requires Sun's Java VM 2 which your browser may perceive as a popup. Which it is not. If you want to see the applet work, visit Sun's website at https://www.java.com/en/download/index.jsp, download and install Java VM and enjoy the applet.

What if applet does not run?

Explanation

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