To set how fast it thinks, we need an external crystal X1 and associated capacitors C1 and C2. Note that the specified crystal could be replaced by a ceramic resonator or crystal in the 10MHz to 12MHz range without any significant change in performance. If you use a resonator with built-in capacitors, omit C1 and C2. At 12MHz, the '2051 will execute an instruction every 1 or 2us. As you can see from the schematic, the 30 LEDs are connected in an X-Y matrix.
Engineering is full of compromises.
I wanted two 'concentric' hearts as more interesting patterns would be possible. This process is repeated for each column in turn taking 10msec for a full cycle. The minimum practical multiplexing frequency is about 100Hz which is the frequency used by the Heart. The power supply uses a common 7805 three terminal regulator with bypass capacitors C4 and C5. Diode D1 provides insurance against a reverse polarity power supply.