flatcubes.py

import bpy
import random
import math

# random seed
seed = random.randint(0, 99999);


def main():

    # set seed
    random.seed(seed)

    # clear all
    bpy.ops.object.select_all(action = "SELECT")
    bpy.ops.object.delete(use_global = True);
    
     
    camera = bpy.ops.object.camera_add(location=(0.0, 0.0, 6.2), rotation=(0, 0, 0))
    
    
    rotX = 0 # random.uniform(-math.pi*0.1, +math.pi*0.1)
    rotY = random.uniform(-math.pi*0.3, -math.pi*0.2)
    bpy.ops.object.light_add(type='SUN', view_align=False, location=(0, 0, 0) ,rotation=(rotX, rotY, 0))
    
    sun = bpy.context.active_object
    sun.data.node_tree.nodes['Emission'].inputs['Strength'].default_value = 9
    
    
    bpy.ops.object.light_add(type='SUN', view_align=False, location=(0, 0, 0))
    sun2 = bpy.context.active_object
    sun2.data.node_tree.nodes['Emission'].inputs['Strength'].default_value = 0.8
    
    
    # sun.nodes.inputs[1].default_value = 5.0 # strength
    
    
    
    
    
    bpy.ops.mesh.primitive_plane_add(location=(0,0,0))
    bpy.ops.transform.resize(value=(8,8,8))
    
    mat4 = bpy.data.materials.get("Mat4")
    ob = bpy.context.active_object
    if ob.data.materials:
        ob.data.materials[0] = mat4
    else:
        ob.data.materials.append(mat4)
    
    

    size = 2
    cubes = []
    
    depth = size*0.7
    cubes.append(Cube(0, 0, depth, size, size, depth))

    division = 90

    for i in range(0, division):
        
        ind = random.randint(0, int(len(cubes)*random.uniform(0.0, 0.7)))
        
        c = cubes[ind] # random.choice(cubes);
        
        w1 = random.uniform(c.w*0.2, c.w*0.8)
        w2 = c.w-w1
        h1 = random.uniform(c.h*0.2, c.h*0.8)
        h2 = c.h-h1
        d1 = random.uniform(c.d*0.2, c.d*0.8)
        d2 = c.d-d1
        
        
        cubes.append(Cube(c.x-c.w+w1, c.y-c.h+h1, c.z-c.d+d1, w1, h1, d1))
        cubes.append(Cube(c.x+c.w-w2, c.y-c.h+h1, c.z-c.d+d1, w2, h1, d1))
        cubes.append(Cube(c.x+c.w-w2, c.y+c.h-h2, c.z-c.d+d1, w2, h2, d1))
        cubes.append(Cube(c.x-c.w+w1, c.y+c.h-h2, c.z-c.d+d1, w1, h2, d1))
        
        cubes.remove(c)



    mat1 = bpy.data.materials.get("Mat1")
    mat2 = bpy.data.materials.get("Mat2") #bpy.ops.material.new()
    mat3 = bpy.data.materials.get("Mat3") #bpy.ops.material.new()
    
    for i in range(0, len(cubes)):
        
        if random.uniform(0, 1) < 0.15: 
            continue
        
        cube = cubes[i]
        
        x = cube.x
        y = cube.y
        z = cube.z
        w = cube.w-0.001
        h = cube.h-0.001
        d = cube.d-0.001
        
        amp = 1
        
        if random.uniform(0, 1) < 0.3:
            amp = random.uniform(0, 0.5)
            
            w *= amp
            h *= amp
        
        min = w
        
        if h < min :
             min = h
        if d < min :
             min = d
             
        min *= 0.2
        # mat1.inputs[0].default_value = (0,1,0,1)
        
        cube1 = bpy.ops.mesh.primitive_cube_add(location=(x, y, z))
        bpy.ops.transform.resize(value=(w, h, d))
        
        mat = mat1
        if random.uniform(0, 1) < 0.5 :
            mat = mat2
        if random.uniform(0, 1) < 0.7 : 
            mat = mat3
            
        ob = bpy.context.active_object
        if ob.data.materials:
            ob.data.materials[0] = mat
        else:
            ob.data.materials.append(mat)
        
        
        
        
        cube2 = bpy.ops.mesh.primitive_cube_add(location=(x, y, z+d+min))
        bpy.ops.transform.resize(value=(min, min, min))

        mat = mat1
        if random.uniform(0, 1) < 0.5 :
            mat = mat2
        if random.uniform(0, 1) < 0.2: 
            mat = mat3
               
        ob = bpy.context.active_object
        if ob.data.materials:
            ob.data.materials[0] = mat
        else:
            ob.data.materials.append(mat)
        



class Cube:
    def __init__(self, x, y, z, w, h, d):
        self.x = x
        self.y = y
        self.z = z
        self.w = w
        self.h = h
        self.d = d



main()

Thank you!

Here are some tiny tweaks to the light creation for blender 2.8
(because view_align is gone and setting strength is different)

    bpy.ops.object.light_add(type='SUN', location=(0, 0, 0) ,rotation=(rotX, rotY, 0))

    sun = bpy.context.active_object
    sun.data.angle = math.radians(10) #softer
    sun.data.energy = 9

    bpy.ops.object.light_add(type='SUN',  location=(0, 0, 0))
    sun2 = bpy.context.active_object
    sun2.data.energy = 0.8