Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.

Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).

There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."

Encoding (MSB is bit 0, b is binary, g is Gray code):

if b[i-1] = 1
   g[i] = not b[i]
else
   g[i] = b[i]
Or:

g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):

b[0] = g[0]

for other bits:
b[i] = g[i] xor b[i-1]
Reference
 Converting Between Gray and Binary Codes. It includes step-by-step animations.
F gray_encode(n)
   R n (+) n >> 1
 
F gray_decode(=n)
   V m = n >> 1
   L m != 0
      n (+)= m
      m >>= 1
   R n
 
print(‘DEC,   BIN =>  GRAY => DEC’)
L(i) 32
   V gray = gray_encode(i)
   V dec = gray_decode(gray)
   print(‘ #2, #. => #. => #2’.format(i, bin(i).zfill(5), bin(gray).zfill(5), dec))