PROBLEM 20
 
 g
 
 g
 
 m = ?gggy = ?gggw = ?ggga = ?gggd = ?
 
 g
 
 (Clue on page 42. Hint on page 45.)
 
 PROBLEM 21
 
 g
 
 g
 
 z = ?gge = ?ggn = ?ggr = ?ggh = ?ggo = ?
 
 g
 
 (Clue on page 42. Hint on page 45.)
 
 PROBLEM 22
 
 g
 
 g
 
 r = ?gggi = ?gggc = ?gggh = ?
 
 g = ?ggge = ?gggn = ?gggt = ?
 
 g
 
 (Clue on page 42. Hint on page 45.)
 
 g
 
 PROBLEM 23
 
 g
 
 g
 
 h = ?gge = ?gga = ?ggr = ?ggb = ?ggy = ?
 
 g
 
 (Clue on page 42. Hint on page 45.)
 
 g
 
 (The problems will now get a little bit harder… .)
 
 g
 
 g