Recreate this formula

Recreate this formula,
after every specific cycles eg 7 or 13 cycles of sine/square wave i have to have phase change of 180degree

;generate
;control HZ "Sine wave frequency" float "Hz" 440 1 10000
;control CYCLES "Cycles between phase inversion" int "" 7 1 21

(setf sq-hz (/ HZ (* CYCLES 2)))
(mult (osc-pulse sq-hz 0) (hzosc HZ))