To create a set of instructions to make Otto walk in a figure other than a square, the following instruction(s) would need to be added to the instruction set:

a. Turn 1 degree, turn is always right.
b. Turn x degrees, where x is a given number of degrees in an angle, turn is always right.
c. Turn x degrees, where x is a given number of degrees in an angle, turn is always left.
d. Any of the above.

d. Any of the above.