This is a modern take on the original Garner oscillator, unlike other versions this one won’t lock up in full conduction and is guaranteed to always oscillate using modern parts, whereas the original -after a few modifications- would only seem to work with germanium transistors.
The modifications are clear, we basically introduced a series resistor to limit inrush current during the low period, the low impedance side formed by the 10 Ohm resistor in Q2’s path was also adjusted, originally a higher resistance was found. We therefore achieved a safe balance which allows us to revive one of Garner’s proudest moments (Hey why else would anyone patent it otherwise, right?)
Taking this oscillator as a baseline we can introduce other forms such as a sawtooth oscillator (It’s not perfect though!) with the help of our friend, capacitance.
To visualize the output waveform you could use a soundcard or a proper oscilloscope. Since the oscillating frequencies on both circuits are within the audible range you could also use a piezo speaker to hear it.
Fun isn’t it?, feel free to experiment and let me know if you find anything intersesting!.