The CDL (Canal Defense Light) was a form of strobing light mounted on 3 types of British tanks- the Matilda, Churchill, and US Grant. These had armored reflectors that would illuminate and dazzle German observers and gunners (operating PAKs and tanks, as well as infantry weapons of all types). When tested by the British, the dazzling light confused the test observers and gunners and the tanks could not be hit regardless as the light gave the illusion of the tanks heading in a straight line when in fact they were moving side-by-side and also shileding conventional tanks to the rear. This was an amazing weapon, so 300 were built for use after D-Day. However, the British Generals disagreed with the usage of such tanks. They believed that they were still vunerable despite British tests and that the Germans would deploy countermeasures or that the tanks would hit German mines. The strobe device had 13 million candlepower and was quite efective in testing. But this is a great What-If considering that ultimately they were not deployed!!!

http://www.wired.com/images_blogs/dangerroom/images/2008/05/16/cdl_matilda.jpg http://www.wired.com/images_blogs/photos/uncategorized/2008/05/15/cdl_grant_3.jpg