Beausant 

The Battle Flag of the Knights Templar that consisted of two vertical blocks, one black and one white.  The black is said to be symbolic of the world of sin the Knight Templar left behind and the white is said to represent the move from Darkness to Light. Does moving from Darkness to Light sound familiar to any of you? See "The Hiram Key" p34.

It is said that many Lodges have a black and white chequered floor which may be emblematic of the Beausant. (See "The Hiram Key" page 34) 

Note: The author of this site has never seen a Lodge with a black and white Chequered Floor.