Source 6a

No. 57. "Big Willie" (also called "Centipede" or "Mother" Tank) Jan. 1916.

[The photo shows a tank climbing up a hill in a woodland setting.]

Source 6b

THE TANK
is a travelling fortress
that clears the way for
our soldiers.

It cuts through the wire - under fire
It saves lives
It is our War discovery
It is a matter of pride to help to
build Tanks.

[The poster is an illustration of three tanks in a battle scene, with explosions nearby. They leave behind them barbed wire and muddy ground, and are followed by foot soldiers carrying rifles with bayonets.]

Source 6c

No. 91. Whippet or Medium "A" Tank.