This step stool design was created by Herrick Kimball in 1987. The top has a hand-carved child's name. Carving how-to can be found in the YouTube video titled, Letter Carving With A Simple Utility Knife (link: https://youtu.be/sofzNd3Y3qU)
The assembly process is shown in the YouTube video Making Stools For My Grandchildren in My Outdoor Workshop (link: https://youtu.be/-OPX7UOob4o).
You can learn more about this stool and other products created by Herrick Kimball at his web site: Planet Whizbang