Is that what they call a Puzzle quilt block?

Anita Grossman Solomon has several books out on this technique. She shows multiple types of results. One is a type of "crazy quilt".

tutorial for crazy 9 patch:
http://www.ohfransson.com/oh_fransso...ice-quilt.html

this is the way i did the one in the picture posted above..

it was done "quilt as you go" method.

Colourwash and bargello are done like this and so are some of Ricky Tims' quilts.

Unless the word "random" means something different across the pond I don't think bargello or stack and whack fits the bill. However, stack and slash might work and I found the pattern years ago on-line for free.

It could be a take five or turning twenty where you cut the fabric and take the first one in the pile and put it on the bottom and then the next pile put two on the bottom etc.

Could you be thinking of "Layer Em Up" by Sharyn Craig?
She has a tute where she uses 4 - 6 squares, stacks them, and cuts them then takes peices of the top and puts them on the bottom so as she sews production line each block is different? Just google it. If you can't find it, let me know and I'll try to find it again for you.

Its called a crazy shortcut quilt. I made one(large queen) and enjoyed making it. I could use lots of the machines decortived stitches. It use to be on utube video.

There's another pattern that starts with a 15-inch block. You cut two parallel vertical lines then two parallel horizontal lines.... then you stack the pieces in different ways. It is called magic tile.
You sew black fabric between the resulting pieces and it makes
a gorgeous stained glass look. It's more work than the stack and whack but the effect is wonderful - especially if you use fabrics that have some gold in them.

I believe it is called stack the deck.