Category:Tektronix

These were plotted using a Tektronix graphics computer^[1] sometime between 1975 and 1978 or so.

All of the designs are based on wide-interval samplings^[2] of sine waves plotted in various different ways. This was a technique I discovered more or less by accident when I mistakenly had the trig functions set to "RAD" (radians) with a plotting program that was designed to work in degrees.

I wrote the plotting program in BASIC, because that's what was available (I think that was probably the first programming language I actually used successfully^[3].) I wrote the program in the first place because I wanted to see what shapes you get when plotting various sine functions using polar coordinates. (Sine waves are fun. Polar coordinates are also fun.)

Footnotes

↑ I think the model number was something like 3017, though Wikipedia indicates that it was the 401x series which was active at that time -- so maybe it was 4017, 4016, 4015? I don't know if there are any photos... (Update: 4015 is starting to ring a bell, so I think that's what it probably was.) It had an integrated QIC tape drive, and the screen was a bit smaller than the ones used on the original version of Battlestar Galactica.
↑ Feel free to ask me to explain what I mean by this.
↑ : I had tried to write in FOCAL-69 in 1972, second grade, but I misunderstood the line-numbering system and my programs all executed out of order... and it's difficult to create any output worth looking at when your output device is a teletype. (A VT52 was later added, for those occasions when you don't actually need a complete printed record of your entire debugging session.)