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A frog is located on a unit square of an infinite grid oriented according to the cardinal directions. The frog makes moves consisting of jumping either one or two squares in the direction it is facing, and then turning according to the following rules:
i) If the frog jumps one square, it then turns
to the right;
ii) If the frog jumps two squares, it then turns
to the left.
Is it possible for the frog to reach the square exactly
squares north of the initial square after some finite number of moves if it is initially facing:
a) North;
b) East?
i) If the frog jumps one square, it then turns

ii) If the frog jumps two squares, it then turns

Is it possible for the frog to reach the square exactly

a) North;
b) East?