Giant LEGOs--that aren't QUATROs? We got a big tub of secondhand LEGO bricks, and included was a random pile of what appear to be giant LEGO bricks. They are a bit bigger than DUPLO bricks but smaller than QUATRO bricks and have an old style LEGO logo stamped into the studs. They're all the same size. What's the story of these bricks? 

Here's a picture of them. I've put a DUPLO in the picture for scale ;-)
I think these are LEGO Jumbo Bricks from Samsonite. 



Left to right: normal brick, duplo brick, Jumbo brick and Quatro brick.