Squared shadows after rendering I would like to ask for a help. I have draw simple object with lights, but there was some squared shadows after rendering. (visible on the top and on the left side of the objects). There could be some consequence with size of the object (about 5mm). Unfortunately I have no Idea about solving Blenders sensitivity during rendering, antialiasing, or some other issues related with problem.

Do you know how to fix this object?
Thanks for replies!

EDIT:
I have just tried to change the buffered shadows to the ray shadows. The result is much better, really big thanks for buffered shadow information, that in base solved my issue (image is usable now), but there are still small squares. Is there somehow possible to create image even better? (This is just for my interest now, not because of some real trouble) The image is shown below.
Thanks all, problem solved. Squared shadows was solved according message user2859 in the spot settings, which erased the highest squares.


There was some other little squares after that, although image was usable after this setting. According user2859's next message I changed antialiasing settings in the rendering settings.


After theese steps was issue solved. All scopes settings(Waveform O, Vectorscope opacity, and Scope samples(the top left button on the window during rendering)) was on maximum during the tries.