How many pillows?

Once upon a time a bed used to have two pillows for every person who used it, but this age old rule no longer seems to apply, and certainly not in my house. We do have a pretty big bed, it comes from Norway and is a 'super-king', which means it's almost 2 meters wide, and it takes three pillows across it's width, however we actually have 10 pillows on our bed. Apparently some of them aren't pillows at all but are in fact cushions, not that I'm at familiar with whatever the difference is between a pillow and a cushion. We also have this other thing that lays across the bed just in front of all the pillows (or cushions) that seems to serve no obvious purpose at all. I have no idea what it's called, but it apparently needs to be removed when we're in bed and put back on when we're not.

We were at my mother in law's place this afternoon and moved some furniture around in her bedroom for her. When we were almost finished she put the new linen with two pillows on to her bed, and asked me how it looked. I said I thought it was fine except she was apparently three pillows short. She looked very confused and asked me what I meant - I still am very confused and told her I didn't have a clue.