Combining Spheres with Cubes

Hello,
could someone show me how to combine the lower sphere with the cube.
Top one no problem, but the lower one, i just cant figure it out!Thank you in advance,

Maybe like this? Is this "correct"?
Cheers,
Fritz 
@fritz Hi, it doesn't look right. Imagine that you have an apple and you need to connect it to a box. How would you slice it, so there is no space between apple and the box? In you connections there is a lot of spaces. Good luck!

Hej thx for your answer well that's what I can't imagine. Do you mean on the bottom line make the circle rounder? A quick sketch would be much appreciated

@aska and I think on my very last image it looks quite right, I just have to work on the roundness?!

You have to visualize the place where the sphere meets the surface of the cube: this is always going to be an ellipse or a section of ellipse  small sketch below. The "Vshaped" indentation that you see when the sphere strides one of the corners can only be at the corner itself  yours is not in the right place. It helps to draw a raster on the faces of the cube to help visualize the surface in your mind. I would also try to draw more precisely in general  your cubes are not very "cubic" ;). That makes visualizing the intersection even more difficult.
These exercises are always interesting and really help with drawing! 
Oh wow thank you, so i will have a look

Hej smceccarelli,
i just did a quick resketch of your sketch to get a visual feel. Thank you so much.
I know my cubes are not so cubic, and my circles are not superround.
I almost broke apart of my perfectionism so i decided just to let go and draw more losely. I want to improve, but at the same time i have to be careful not to be too hard to myself. But i'm drawing every day because its fun to me.So here is my resketch. I will work on the details now. I really wanna master the art of drawing. I'm very thankful therefor that you made this quick sketch for me.
This is the answer i was looking for. Now it makes totally sense.
And your artwork is amazing by the way!Have a nice evening,
FritzP. S. it could be, that i'll have more questions about combining shapes of different kind

Happy to help  and these exercises are good for me too!

@fritz sorry, I was busy with kids earlier, but maybe thats better cause @smceccarelli is a drawing gem