Can someone please uncompress this line and tell me how it works?
grid = [[0 for x in range(22)] for y in range(22)]
Is this a list of lists or a pair of lists or what? It appears to create what in languages of the past I would call a two-dimensional array. Addressing this object takes the form
grid[1][1] = 1
or
print(grid[99][99])
So the indexing is familiar, but I don’t understand what the thing is, exactly.