Circuit diagram for wave generator
The circuit shown produces a pretty good square wave (10 V peak-to-peak) able to drive a low impedance load, and a slightly curved triangle wave of lower amplitude, and only able to drive a high impedance load.
The 555 "timer" chip in the figure is shown with its pins in the actual DIP8 layout (pin 1 is upper left)
The time constant is T = R1 * C1, which here would be 100uS. I measure a repetition rate of 3KHz.