Just noticed that it is possible to generate the waves, at-least a similar looking result using Levels > Envelope. The following is what was done:
Create a 432 Hz sine wave for 1/7 seconds (or 142 ms) duration using Tonegen
Edit the tone in Wavepad
Go to Levels > Envelope section
Move the dots in the section to make it look like a trapezoid (square wave with tapering start and end), and save it as a "Trapezoidal" preset if you like
Apply the preset
This would make it just one component of the wave. Many such components have to be joined together to get the entire wave