I wasn't aware of the Spectrum demo scene at the time, but I spent a lot of my time writing basic programs to produce interesting visual effects, randomly rewriting the character set, make use of the random function with plotting, etc.

At around the same time, Jeff Minter wrote 'Psychedelia', https://en.wikipedia.org/wiki/Psychedelia_(light_synthesizer), which was ported to the Spectrum. Computer graphics were primitive but for the first time, you could control the imagery on your TV set without any kind of video camera or VCR and that felt like a very big step forward.

I have long since lost all my program tapes, but when I was packing to leave our old house last year, I came across an old school diary with a mysterious listing;

Revise This Week?

So - what does it do? As a 4 line program, it didn't seem as big a risk as your average type-in listing of the time, so here it is;

10 BORDER 0 : PAPER 0 : INK 7 : CLS
20 LET e=255 : FOR x=0 TO e STEP 2 : PLOT x,0
30 DRAW e-(x*2), 175 : OVER 1 : NEXT x
40 PAPER 7 : INK 0

Pretty simple; invert the screen for a more atmospheric look and a simple loop to draw 255 lines within the screen boundaries. The function looks pretty simple and the last line is, in fact, redundant. So what does it output?

So there you have it, a very simple drawing routine that renders a charming 2001-style effect!