Hi Mark, thanks for the message. If your blinky failures are checksum errors, that usually indicates an issue with the data sensor (as opposed to the clock sensor), so you might take a look and ensure that you have good solder joints to the data sensor and resistor R2 (next to the pushbutton). Issues with the clock sensor tend to manifest as "stuck at end of programming" since it missed some clock edges.
In general, ensure that your screen brightness is at 100% (even 99% won't work, as most displays just switch the backlight on and off rapidly to produce reduced brightness levels, which tends to mess with the programmer's switching signals). Also try setting the delay to something absurdly long like 3000 and see if that works reliably. If so, reduce the delay until it stops being reliable.
You can also get a voltmeter or multimeter to measure the DC voltage between ground and the pin labeled + on each sensor during the programming process. Be sure to use a large delay like 3000 or 5000 so your meter has time to settle down after each transition. You should see a larger voltage when the sensor is pointing at a white box, and a lower voltage when the sensor is pointing at a black box. The chip observes this difference in voltage to sense the white and black boxes. What voltages do you observe?
It's been a couple years since we wrote that code, but I believe that the easter egg only works on the blinky pov, sorry
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