There is a cool group on Facebook called "Electronics Theory and Circuit Design". People have interesting ideas, the group has good spirit and culture.

But I had this not-so-nice discussion with a new member called Doug Hale. He proudly presented XY scope photos with a circles on a rectangular raster. Nice, but I was not impressed. I said I can do it with a quadrature generator, 2 staircase generators using cascaded counters, R-2R DACs and summing amplifiers. Nowadays Direct Digital Synthesis (DDS) with a 1$ STM32 equipped with a 12-bit dual DAC. But Doug Hale was so proud his solution was all analog, that he called me ignorant and limited, "few can do what I did, you can't", "you are not my audience". Oh, really?

Doug Hale, I think you are wrong in 3 important aspects:

• You can confine yourself, but you cannot confine me. What confines you the most is your knowledge. But I can restate the problem as I see fit. That is how science works. This is how I work.
• You cannot choose your audience. The audience chooses you. The word "audience" comes from Latin "audio" - "I hear". You can speak, but it is me who decides to listen or not.
• Insulting people is not a sign of strength. It is a sign of your weakness.

I did rotating rectangles, which he could not do:

He challenged me to do a caption. I promised to publish it here. Offered him an option to apologize, but he preferred to be impolite.

So here it is. It reads "Doug Hale can't do it". You can test your scope XY function and your playback device by plaing doug_hale.wav. The file is 14 MB / 1 min 23 sec big. You might need to disable equalizer and set maximum volume. Terminating the output with some 22-47 kΩ resistors helps to reduce noise. Sometimes playback is inverted,so you might need to play doug_hale_neg.wav or play with the scope gain sign.

I had good success with my HP laptop (inverting) and Samsung Galaxy tablet (non-inverting), but not with my IPhone 6S, which does not seem to reproduce the required low frequencies well.

Doug Hale has left the Facebook group, leaving behind nothing but bad air. If you meet him, tell him he is famous on the Internet.