Hi there,
there seems to be a bug in pygame.draw.ellipse, where if either x or y of size is odd, then the resulting eclipse will have a real size of x-2, y-2.
So basically, to draw an ellipse that has 3 x 3 pixels on the screen, one needs to use pygame.ellispe.draw with a size of 5 x 5.
Best,
Florian