So when i was waiting for my friend for lunch downstairs in his office, i was standing at this new building and they have very nice "cement" walls. I couldn't resist but to whip out my phone and took a few shots. They were gray in color and with slight texture. Here, a photo of how it looks like below:

I know, it's just a plain Gray wall. But isn't it nice? Imagine the possibilities that you can use this? 
So, i knew i had a drawing lying somewhere where i got it scanned in Black and white. Here's a picture below:

And then i worked out my magic on Photoshop and about a couple of minutes later (well maybe 30-45 minutes) Here's the outcome:

You can also check out the post here on Dribbble. Hope you like it!