Warning: major room envy ahead.
The trick when designing for young kids is to build a foundation of a room that can easily adapt to the changing definition of "cool" throughout their stages of life. For a toddler, coolness might mean a wide open, soft area to learn to walk and play on. For elementary kids, it might mean the addition of a Lego table. For tweens, it might mean more dedicated display storage for trophies or hobbies, or (in the case of an example below) the addition of a climbing wall.
Take a scroll to see some of our favorite rooms, specifically tuned to the needs of kids in very specific stages of life: