Above is Scott's Crystal Oscillator circuit I failed with due to not having correct value parts (and it seems crystals are a pig to get oscillating on a breadboard anyway!), so moved on to his astable multivibrator circuit instead. I had some hassle getting this thing going too due to bad bread board connections (used 2N2222 transistors), as with no caps, the LEDs light anyway but stay on!
I changed Scott's 10uF to 100uF caps to slow it down,- to be sure I could see change. Later, when working, the 10uF caps gave- a 16.8Hz ramp -- an annoying flicker rate! 100uFs gave a 1.39Hz ramp.
Move your probe to different places to see the various ramp waveforms possible.