I have not seen the Auto Tri Huevo before, looks like the offspring of a Scootacar and an ISO Isetta.
The Hungarian one is in Julian Nowill's excellent book East European Cars. If I remember correctly it was home-made, with a body made of home-made version of plastic/fibreglass: chicken feathers dissolved in nitric acid, the glop then moulded, dried, and protected with shellac, but apparently it did smell "agricultural" in damp weather.