I really didn't know what to expect with this exchange, since I'm definitely not engineering-minded or experienced with making anything at all. Given that, I am SO EXCITED about my gift, which is both relatively simple to put together and so much fun once it's finished! I just picked up the package about 2 hours ago, and I've already made the Stirling engine and it's happily chugging away in my windowsill! I had not even heard of this type of engine before, so this also acted as a small educational experience. Thank you so much to my gifter! This will definitely have a place of honor in my living room or at my desk at the office!