> "Those pointy corners look more typical trochoid than "typical lissajous". What calculation artifact corresponds to a line wheeled-over to form a trochoid loop? Not sure "hysteresis" explains this best."

I'm creating that phase-space waveform myself through a solution to a differential equation so know exactly what is causing the shape, which is a sample-and-hold lag integrator with a delta spike that is incommensurate with the clock frequency.

![](https://imagizer.imageshack.com/img924/9426/dMpqsD.png)

![](https://imagizer.imageshack.com/img922/4291/UUwE0h.png)

This is not difficult, especially considering that this is the kind of stuff that shouldn't be a problem to reverse engineer -- since the time variable is missing from the phase plot.

Consider this guy asking what's causing a similar pattern on stack exchange

https://scicomp.stackexchange.com/questions/10493/fit-my-data-to-lissajous-curve-in-matlab

![](https://i.stack.imgur.com/2wCQY.png)

Everyone tries to be so helpful, but the questioner should realize that he could figure it out himself if he left the time-scale in his data acquisition and plotted y(t) vs t (i.e. potential) and dy/dt vs t (i.e. current) side-by-side. Then he would see it is just a square wave, with likely some noise on the top.