Most computers can’t create true random numbers. They use a formula which makes a very long stream of pseudo-random numbers, but real randomness comes from thermal noise in analogue components. The Raspberry Pi has such a circuit in its SoC, as it helps making the seed data for secure transactions. It was only recently that a driver for this circuit was supplied. To enable it (on Raspbian)...

I tried it on mine, it randomly spit out a couple of raspberries....it could be that my office gets way too hot. ;-)

Ha! That's a sweet raspberry you have there...