This is a LEGO Pencil Holder that my 7 year old son and I designed and built during the Shelter in Place order in California during the COVID-19 lockdown of 2020.
It was designed using Studio from BrickLink.
Studio is a desktop application that allows users to build LEGO models using virtual parts. Users will have the freedom to build anything they want with any LEGO part. By being integrated with the BrickLink catalog, Studio can do things like showing you what part colors are unavailable and letting you keep track of part costs. Studio also makes it easy to turn a finished creation into a wanted list that you can use to order through BrickLink.
Studio is completely free to use and runs on both Windows and Mac. Although a BrickLink account is not necessary to run Studio, registered users will have the added bonus of being able to build with friends in real-time.