This picture is in time with the average heart rate. What you’re hearing is the sound of your blood pumping, which you aren’t normally aware of. This picture tricks your mind into making yourself aware of your heart rate, so you hear it.
“According to Greek mythology, humans were originally created with four arms, four legs, and a head with two faces. Fearing their power, Zeus split them into two separate beings condemning them to spend their lives in search for their other halves.”