There is a sort of electronic sign called “Beta Bright” which consists of an array of LEDs about 120 horizontally and 7 vertically. Horizontal and vertical distance between the LEDs is about the same. Text flows across the display from right to left so that we can read the text from left to right. The eye moves continuously tracking the text and moving text seems to be composed of little round red dots just the size of the real LEDs. Since the view field is moving relative the dots should appear blurred horizontally unless the LED spends most of its time off, which evidently it does. The top of the text appears to be one dot further to right than the bottom of the text and the lines of dots between are along a line slanted to the right at the top.
In a bit more detail the text velocity was nearly 10 cm/sec and the pixels were about 0.5 cm apart in each direction. The flowing text seemed to have the same distance between pixels. The amount of slant skewed the top about 1 pixel at the right
The question is which order the lines are displayed to give this pleasant effect, from top to bottom or the other way. This question is confusing enough that I have not been able to be sure of the answer without writing down the intermediate steps.