Why is this?

[Jiri Barton]

Yes, now it is clear!

As always, I should have RTFM, the operator* is not just a syntactic sugar
and thus does not make copies. You know, my actual scenario was with four
variables at the time:

a, b, c, d = [], [], [], []

so I was even more tempted to use the previous and wrong approach:-)

Thank you for your explanation. No more errors in my code from now on (oh
well,...)

jbar