Expression 7: "y" equals left brace, mod left parenthesis, "x" , 1 , right parenthesis less than 0.5 : mod left parenthesis, "x" , 1 , right parenthesis times 4 negative 1 , right bracey=modx,1<0.5:modx,1·4−1
7
Adding another piecewise part for the second half
8
Expression 9: "y" equals left brace, mod left parenthesis, "x" , 1 , right parenthesis less than 0.5 : mod left parenthesis, "x" , 1 , right parenthesis times 4 negative 1 , 3 positive mod left parenthesis, "x" , 1 , right parenthesis times negative 4 , right bracey=modx,1<0.5:modx,1·4−1,3+modx,1·−4
9
And a slightly more complex version to handle variable frequencies.
10
Expression 11: "y" equals left brace, mod left parenthesis, "x" times "f" , 1 , right parenthesis less than 0.5 : mod left parenthesis, "x" times "f" , 1 , right parenthesis times 4 negative 1 , 3 positive mod left parenthesis, "x" times "f" , 1 , right parenthesis times negative 4 , right bracey=modx·f,1<0.5:modx·f,1·4−1,3+modx·f,1·−4