[ghusbands]

I'm talking about televisions and similar. You are still simply wrong. Nearly all of the 8-bit and 16-bit consoles and computers that output to CRT default to non-interlaced, without the TV alternating fields.

Look at other responses in this thread to see how interlacing used to be achieved and the flexibility it had.

[TazeTSchnitzel]

Ah, I see now. Your comment about the half-length scanline made me understand.