It's very easy to get confused by this. A horizontal bar is refers to the horizon: i.e, right to left. aka the x-axis a series of hbars will stackabove and below .. sure this gives it a verticial character but that is because there are several. A single on is horizontal. vbars are therefore the oppostie,
This is a hard one to work out. Yes. I got into a tizzy about binary and even this simple figure ties into binary structuring.