Strange tank (4 photos)

What a contraption from this tank? It seems not fake, because it really existed tank.

"Sentinel" (eng. Sentinel) - Australian cruiser tanks of World War II, the average weight. It was created in 1942, when Australia to repel a Japanese invasion which threatened urgently needed a tank that can be done entirely by Australian businesses. In 1942-1943, it was released 68 "Sentinel" in several ways. The tank was used by Australian troops until 1945, exclusively for educational and training purposes, since by 1943 have become available more sophisticated tanks "Sherman" made in the USA.