I don’t intend to beat anyone…

But Maris brought up one interesting aspect.:
Though that Fred Picker quotation seems quite convincing, we are sorrounded by A-verticals.

But why is film horizontal? Why is my computer screen horizontal, and can’t I write decently a letter on it?

I never thought a lot about this, but it could be interesting to look back into history how all these aspect ratios (especially including that vertical/horizontal issue) evolved in man’s cultural development (or movement…) over all kind of outings: painting, printing, photographing, filming etc.