plot~ amplitude

Those pictures were probably cheats done in a graphics program, just for the purposes of demonstrating how the messages to line~ result in signal output. However, with some additional patching, it's possible to get plots like that. The plot~ object is pretty good, but — because it's designed to be able to plot many kinds of data in many ways — it does require that you specify a lot of parameters in order to get it to look the way you want, . Here's an example of how you could obtain a plot like the ones you mentioned.