I’ve been a lifelong reader, a fragile habit in our era of endless distraction. Books and e-ink readers solve attention competition but can’t compete with a phone for convenience. A few days ago, I learned about tiny e-ink readers. I bought an Xteink X3 and installed the open-source Cross Point firmware. I added books and custom fonts, though rendering was indifferent.

Cross Point is configurable, so I converted a photo to a dithered bitmap for my sleep screen. When I read the device supported 4 shades of grey, I tried greyscale. This revealed a bug: dark grey rendered as black. I created a test image and confirmed it. A three-tone image showed ghosting in the viewer app, but not the sleep screen. Both had vertical stripes not in the bitmap.

Knowing nothing about e-ink or ESP32, I used GPT-6 Astra in Codex. Astra found the viewer did a fast black-and-white update without the grey nudge, and fixed it. The stripes persisted. Astra blamed Floyd–Steinberg dithering, then flagged the nudge waveform. It reported a two-pixel stripe pattern, but annotation showed it picked dither texture, not the bands I saw.