Two sine voltages (e.g. representing measured voltage and current) with the same frequency but different phase shift are multiplied, thus showing the instantaneous power. Try different phase shifts.
Both amplitudes are choosen as 5 V, i.e. 0.5-times the maximum value (Vscale= 10 V).
The result (sine squared) - arithmetic mean (i.e. real power) deduced - has an amplitude of 5 V * 5 V / Vscale = 2.5 V.
Bear in mind the different scaling of the output!
The arithmetic mean i.e. the real power is 5 V/√2 * 5 V/√2 / Vscale * cos(phase shift=45°) = 5/8*√2 = 0.8838834765 V.