Hello there!
I'm creating this topic to advertise my creations! Yes, that's right. Because I think that some of them are quite good, especially my fission reactor (https://powdertoy.co.uk/View.html?ID=9238). I have used some ideas from other people's creations, but there's too many to list them here. Please, tell me what you think and give me some new inspirations/ideas! Thanks in advance.