It is difficult to camouflage a battleship. I know I am preaching to the converted here; this is a realisation we have all arrived at on our own.However during WWI, faced with changing weather, various climatic conditions and the insistence of the Germans in sinking their boats, the British Navy had a crack at it. Norman Wilkinson, developed a series of patterns, based on cubism that did not try to hide the ship so much as disrupt the viewing of it.

These boats were the Dazzle Ships. The theory was that U-Boat Captains, staring through their periscopes, would have difficulty judging not only the distance to the enemy target but also which direction it was moving. Thus making aiming a torpedo troublesome.

The Clover. Sketch above, reality below.

Perspective deployed as an evasive tactic.

[update] Rob provides some notes on the world of the Camofleur, an afficianodo of Camoflage.