Hi,
Heres my 2/3 sheet of foam and some copy paper build that I made right at the beginning of the quarantine. I sadly didnt take a super early picture, but in the pictures you can see how its constructeted from scratch (didnt use plans, but a three-view)
Its a Henschel Hs P.87 , a German bomber concept from WWII.
I first made a profile-plane, then I cut out some ribs to form the body and then I covered it with normal copy paper. I also made a spinner and painted it completing the look. The cool thing is that its completely closed, so its master series looks on a mighty mini scale (20"wingspan, around Long EZ size). Its powered by a cheap chinese motor-ESC combo that spins the prop from a toy quadcopter. Battery is 350mAh 2S, flying weight is 109 gramms.
Its pretty fast for its size and quick on rolls.
Flight video:
I hope you like it although it doesnt really meet rule 3.