In Hungary it's a pipeline. You go in a room, you pick a piece of paper out of a hat, which gives you some task or topic to prepare for. Then you sit down at a desk (the room is filled with about 15 students working already), then you solve the problem or sketch out your notes to present the topic you picked for like 20 minutes, then you go to the professor and you have to, in low voice, explain your solution, the professor asks back and pokes at it to make sure you understand. The professor then gives a grade immediately and you go home.

In Germany, it's usually no random pick of a topic, you just go through the entire semester's material over 30-45 minutes and the professor stops to spend more or less time on each topic to explore your knowledge. You can explain things by making sketches on paper. A PhD student sits there quietly taking notes of what was asked and what the student answers approximately. You leave the room, the prof and the PhD student discuss the performance, decide the grade and you come back, and the professor explains the grade and what you did well and not well.