Source: C++ For Dummies, 7th Edition by Stephen R. Davis (2014)

Example:

Return to our PC-screen-repaint problem. Surely it must need a loop structure of some type to write each pixel from left to right on a single line. (Do Middle Eastern terminals scan from right to left? I have no idea.) What about repeatedly repainting each scan line from top to bottom? (Do PC screens in Australia scan from bottom to top?) For this particular task, you need to include a left-to-right scan loop within the top-to-bottom scan loop.

I understand the joke about the Middle East because everybody knows that in Arabic they read from right to left. But what's that about computer screens in Australia that scan from bottom to top? What's the humour here?