Expression 3: polygon left parenthesis, left parenthesis, "a" , 0 , right parenthesis , left parenthesis, left parenthesis, "a" , "f" left parenthesis, "a" , right parenthesis , right parenthesis , right parenthesis , left parenthesis, 4 minus "a" , "f" left parenthesis, "a" , right parenthesis , right parenthesis , left parenthesis, 4 minus "a" , 0 , right parenthesis , right parenthesispolygona,0,a,fa,4−a,fa,4−a,0
3
Hidden a: left parenthesis, 0.7 , negative 0.1 5 , right parenthesis0.7,−0.15