A brick wall made of randomly sized bricks

Hi
I am a new learner of GH, I’m trying to build a brick wall made of randomly sized bricks (like below). The size of these bricks varies randomly along the x and y axes simultaneously,Some of them are rotated,and some of them are protrude or recede randomly. I try my best to restore it,but However, I failed to complete the first step. I think my thinking may be wrong.
Please help me

Some links

http://www.co-de-it.com/wordpress/code/grasshopper-code

Thanks a lot, I’ll trying to finish this with your help! and I’ll post it if i have difficulties.
Thanks again!