Design 3

I did Design 3 - a house.

Step 1.
I put a box shape on the workplane and scaled it to the size 49×36×36. Then made it purple color.
Step 2.
I put another box shape and scaled it to the size 1.50×0.75×19. Made it yellow color and put it in front of the purple box. This is a door.
Step 3.
I put a workplane on top of the purple box and put a roof shape. Then scaled it to the size 54×39×10.
Step 4. 
I dragged a box shape on the workplane and scaled it to the size 11×12×48. Then I dragged it inside the house to the corner, so it will look like a chimney. And later made it purple color.
Step 5.
I put a workplane on top of the chimney. Then I was putting 5 sphere shapes size of 10×10×10 on top of each other, so it would like smoke coming out of the chimney. After, I grouped the spheres and made them light grey color.

So, this is what I had after I finished the steps above: