Ah, the T-34. I can see the discussion for its creation now.
Russki A: Dah, Comrade, we shall put the biggest gun we can find, and strap it to the nearest tractor chassis.
Russki B: Very good, Comrade. And what sort of armour shall we put on it, and aiming system - oh, and what about crew comfort?
Russki A: *Blank look of incomprehension*
Russki B: I make joke!
But with a bit of Russki ingenuity, I heard tales that they created reactive armour by strapping mattresses to the tanks. The springs caused the explosions of shells to 'bounce'. If they hit springs of course, otherwise everyone inside went deaf immediately and then died.