Heart-shaped flowing light

I. Circuit Function:
        After power-on, 18 LEDs blink clockwise.
II. Circuit Principle:
       The 18 LEDs are divided into 3 groups, driven by 3 transistors. It's best to use one color or 3 colors, because the LEDs in each group are connected in parallel. Since the driving current and voltage for each color LED are different, if there are many colors in one group, some LEDs will not be bright enough, affecting the display effect. When the power is turned on, the 3 transistors will compete to conduct, with only one transistor conducting first. Let's assume Q1 conducts first. The first group (LEDs 1, 4, 7, 10, 13, 16) will light up. Because Q1 is conducting, its collector voltage drops, causing the left end of capacitor C2 to drop close to 0V. Therefore, the base of Q2 also reaches approximately 0V, and Q2 is cut off. Thus, the second group of LEDs connected to its collector is off. At this time, the high voltage of Q2, through capacitor C3, raises the collector voltage of Q3, and Q3 will also quickly conduct, lighting up the third group of LEDs. Therefore, during this period, the collectors of Q1 and Q3 are both at a low level, the first and third groups of LEDs are lit, and the second group of LEDs is off. However, as the power supply charges C2 through resistor R2, the base voltage of Q2 gradually increases. When it exceeds 0.7V, Q2 changes from the cutoff state to the conduction state, and Q3 changes from the conduction state to the cutoff state, its collector voltage increases, and the third group of LEDs turns off. Next, the circuit cycles according to the process described above, with two groups of 12 LEDs lit simultaneously. These LEDs are arranged in a cross pattern to form a heart shape, continuously flashing and emitting light in a loop to achieve a flowing display effect.
III. Precautions:

Operating voltage: 2.5-5.5V;
The longer lead of the LED and the electrolytic capacitor is the positive terminal, and the shorter lead is the negative terminal.