What's with the weird assignment behavior in python?

Question

Python

After a seemingly unambiguous assignment, the value changes in two places at once.

print (squares)
squares[j][orientation][1] = place
print (squares)
#j = 0, orientation = 1, place = 5

[, ]
[, ]

Answer 1

At indexes 1 and 3, you have the same object.
A possible solution (probably not optimal, you know better from the context) -

print (squares)
tmp=squares[j][orientation][:] #  создаём копию
tmp[1] = place
squares[j][orientation]=tmp
print (squares)

Google "mutable"