I'd go for a minimum of about 12 layers of 4 bricks to not have too much repetition. After that, pick a resolution that still has some detail for the morter and brick.
You'll probably end up with at least 500x500 pixels for that.
Alternatively you can try to use the cinerender procedural shaders, but you'll need a fair few of them combined to get a nice looking result.
Erwin Edel, Project Lead, Leloup Architecten
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