I miss pic so much. It is a macro processor for troff, that is not used so much any more and for good reasons. But pic was amazing, so simple and yet so powerful. Probably the ancestor of all including tikz.
I've only discovered pic when it got mentioned in a previous thread (there was a Show HN for something called Code2Flow if my memory serves me well). I first thought it was about the Intel 8259 (Programmable Interrupt Controller) or Microchip's uControllers.
As for tikz, I've used pgfplot and tickz + matlab2tikz[0] to produce TeX PDFs from MATLAB figures (it can only export figures as raster or MATLAB .fig, unusable elsewhere), and include those in a bigger PDF (given the number of figures, they had to be generated separately and then included because the memory usage was just too high).
Fig1: Upper is a cleaned ECG signal. Middle is a Time-Frequency representation using an "Adaptive Optimal Kernel"[1]. Bottom is a Time-Frequency representation using Stockwell Transform. They look gorgeous embedded and you can zoom, contrary to MATLAB PNGs.
Fig2: baseline estimation using asymmetric least squares[2] (they used it to clean [spectro/chromato]graphy graphs and I tried it on ECG. It's really cool).
Link: https://en.m.wikipedia.org/wiki/Pic_language
In which I just learnt that there exists a stand alone version that produces svg: https://ece.uwaterloo.ca/~aplevich/dpic/